What is a "Tankie"?
A tankie is anyone that defends authoritarian state-capitalist dictators and the atrocities they've committed and continue to commit.
The term was originally coined when the USSR sent Russian T54 tanks into Budapest, Hungary on the 4th of November 1956 to suppress a worker uprising. Factories had been taken over nationally by workers councils, in a demonstration of worker self-organization that was at odds with the Soviet's imperialist rule. The Soviet troops eventually suppressed the uprising and restored their rule. Then the USSR sent the tanks in to invade Czechoslovakia in 1968, and Afghanistan in 1979. A decade later, in 1989, tanks were similarly used by another state-capitalist regime to crush student dissidents in Tiananmen Square in China.
Anarchists use the word "tankie" to describe any supporter of authoritarian regimes that claim to be socialist. "Red fascist" is another popular term used in this context. The exception is Hitler's "national socialists", who are simply referred to as fascists. Like Lenin and Stalin, Hitler initially represented himself as a socialist; realizing that appropriating socialism would be useful to gain popular support. Of course, his genocidal actions had nothing to do with establishing socialism, and his so-called "national socialist" ideology was just another form of collectivist-capitalism. It's worth noting that the USSR signed a treaty with Nazi Germany that divvied up much of Europe between the two powers. The Soviets then annexed the countries granted to them by the nazis, drafted their citizens into their Red Army, burned villages full of women and children to the ground, deported scores of people to prison camps, and then massacred them.
The definition of fascism from Unionpedia.org:
“Fascism is a form of radical authoritarian ultranationalism, characterized by dictatorial power, forcible suppression of opposition and control of industry and commerce.”
The close similarities between fascism and Marxist-Leninist ideology are hard to ignore. All four of these features apply to both ideologies. Both Marxism-Leninism and National Socialism masquerade as socialism but in reality have little to do with it and are simply excuses to mount dictatorships, control the local populace, invade foreign lands and stamp out all dissent.
Tankies are people who make excuses to justify the atrocities committed in the name of communism. Tankies crave power and work to create rigid hierarchies to amass that power. They support a totalitarian one-party state that governs all of society with an iron first. They defend forced labor, polluting mass-industry, population displacement, mass surveillance, genocide and brutal punishment for anyone who would speak out against the state or the new ruling class.
They support modern China’s blatant racism and nationalism as they attempt to violently force muslims to abandon their culture in favor Han Chinese culture using “re-education” camps and family seperation policies.
The Cleanest Race: How North Koreans See Themselves and Why it Matters is a 2010 book by Brian Reynolds Myers. Based on a study of the propaganda produced in North Korea for internal consumption, Myers argues that the guiding ideology of North Korea is a race-based nationalism that spawns from Japanese fascism, rather than any kind of Communist ideology.
The book describes how the North Korean government is insular, xenophobic and militaristic. It details a mob attack on Black Cuban diplomats by North Koreans, and the forcing of North Korean women to abort mixed-ethnicity children. This racism is deeply ingrained in North Korean society and promoted by the state’s own propaganda.
Since the 2009 North Korean constitution omits all mention of Communism, Myers argues that Juche is not actually the ideology of the North Korea state. He postulates that it was designed to trick foreigners, especially tankies, into supporting the fascist state. And support it they do, wholeheartily, despite all the glaring signs that it’s a perverse merger between fascism and monarchy. They’ll even accuse you of being racist for not supporting that racist state.
They make the same claim to anyone who is critical of modern China’s extreme-capitalist state, accusing them of “Sinophobia”, despite the fact that the criticisms from anarchists are almost always about China’s institutional persecution of ethnic minorities and their overseas imperialism.
Only a tankie could accuse someone with legitimate concerns about billionaire ruler Xi Jinping's racist (and homophobic) policies of somehow being racist against the Han Chinese people for voicing those concerns. There’s no logic whatsoever to tankie cries that anyone who criticises a racist, homophobic dictator of an ethno-state is being racist or that talking about China’s imperialism means you’re somehow an imperialist being paid by the CIA to discredit “communism”.
Tankies often justify defending these state-capitalist regimes by claiming they are "anti-imperialist" states; as they are in fierce competition with "free-market" capitalist regimes such as the USA. Tankies somehow fail to recognize that state-capitalist imperialism is virtually identical to free-market capitalist imperialism. They take the side of imperialist empires like the USSR or China (and even modern-day Russia) in geo-political conflicts simply because they oppose the USA. They fail to realize that there's nothing revolutionary about favoring one empire over another.
Another common argument they make is that the atrocities committed by their idols were necessary to affect the rapid industrialization of their nations. Marx theorized that the way to communism was through a modern industrialized economy. His theories were written with industrial capitalist states like Germany and the UK in mind, to transition them into socialist states, and then finally onto communism.
This presented a problem for Russia, China and other undeveloped nations, who had very little industry to speak of and simple, agrarian economies. Stalin and Mao both decided that the solution was to rapidly industrialize their territories, forcing mass population transfers from rural areas into cities where the former peasant-class would be forced to work in the state's factories, creating the worker-class that Marx wrote his theories for. These forced social upheavals of course created numerous problems, including millions of deaths and rampant environmental destruction.
Tankies praise these genocidal population transfers because they "lifted the peasants (that survived) out of poverty". But they are measuring "poverty" by materialistic, capitalist standards that are simply of no use to the subsistence farmers, hunter-gatherers and nomadic herders that made up much of the pre-industrial world. Before Lenin, Stalin and Mao's collectivization and industrialization, most peasants were largely self sufficient. Even those living in feudal territories, while by no means free, lived simple uncomplicated lives in harmony with nature; having no carbon footprint to speak of since industry was non-existent. Most enjoyed relative autonomy from the state (which had a far shorter reach), practiced mutual aid with their neighbors, and only needed to work a few hours a week  to produce all the food they needed to survive.
The progression of Lenin’s state capitalism quickly changed all this, and they now had to labor endlessly in grungy, polluted cities or on industrial battery-farms for the state or face being branded a "kulak" and exiled, imprisoned or killed. As bad as feudalism was, it simply didn’t have the concentrated, centralized power that state capitalism forced on every single person within its borders.
There was no escaping the state now. You couldn’t retreat to the mountains to get away from the ruler as countless bandits did before because the new ruler was everywhere. Indigenous people were no longer permitted to maintain their way of life because it interfered with the state’s demands for complete worker homogenization. State capitalism made life much harder for anyone who desired self-determination, simply because it was impossible to evade this new form of superpowered-state. Anyone resisting the state’s rule was crushed.
Stalin's "continuous working week"  was designed for maximum worker productivity, allowing workers scant time to recover from the daily grind of the industrial machine. Citizens were forced to work in cramped, unsanitary factories far from their former homes to meet Stalin's industrial quotas. This was an incredibly difficult transition for people that had lived off of the land for generations. The state even outlawed the planting of small family gardens to ensure the people were completely dependent on the party for their survival.
Nomadic herders in Central Asia and Kazakhstan were especially unaccustomed to this new way of life being forced on them, and their resistance was met with brutal force by the Soviet state, who declared them "kulaks" and confiscated their herds. The resulting famine in this region killed between 1.5 million to 2.3 million Kazakhs. 
Similarly to free-market capitalists, tankies support prisons and a police force, such as the Soviet secret police established by Lenin.
Tankies celebrate Lenin and Trotsky's massacres of socialist revolutionaries, including the Mensheviks, the sailors of Petrograd, the Socialist Revolutionaries, the anarchists, unaffiliated peasants who had their food confiscated and so on. Tankies also celebrate murdering 'kulaks', a word they use to describe any peasant that resisted Soviet imperialism, but especially the Ukrainian peasants that resisted sending all their food to Russia, which they rightly guessed would lead to mass-starvation and one of the worst atrocities in history; the Holodomor genocide.
Lenin: Red Terror
Some tankies support Lenin but reject Stalin and other later collectivist-capitalist dictators, saying they went too far. For this reason, it's important to talk about Lenin's long list of dirty deeds.
Lenin successfully hijacked a popular revolution fought by the peasants and workers of Russia, sabotaging communism to install a state capitalist dictatorship with him as its life-long ruler, and then murdered most of the people that actually fought the revolution. This started a long history of Marxist-Leninists acting as parasitic opportunists; co-opting revolutionary movements started by Marxists and anarchists and thoroughly sabotaging them.
Lenin spoke of state-capitalism as if it would somehow lead to communism, but history shows us it only ever lead back to Laissez-faire capitalism in every single case. Lenin:
"State capitalism would be a step forward as compared with the present state of affairs in our Soviet Republic. If in approximately six months time state capitalism became established in our Republic, this would be a great success and a sure guarantee that within a year socialism will have gained a permanently firm hold and will have become invincible in this country." 
The insistence that forcing capitalism on a society that didn't have it before will somehow create communism at a later date is absolute nonsense. Breaking all your fingers to improve your handwriting would be a more realistic proposition than the idea that state capitalism will give way to communism. Indoctrinating millions of people into capitalism and industrialism, destroying their ecosystem and forever changing their way of life will not lead to communism. Most people born into capitalism will cling to the system like their lives depend on it because it's the only world they know. And since capitalism destroys everything in its path, allowing no deviation from its murderous rampage, it’s not like they’ll have much choice but to stick with it until the bitter end.
Let's take a quick look at the disastrous legacy of the state capitalism Lenin installed.
Starting in 1930, 300,000 tons of chemical waste were disposed of in Dzerzhinsk, one of the main manufacturing sites of chemical weapons in the USSR. The Guinness Book of World Records has named it the most chemically polluted city in the world. In 2003, the death rate in the area had exceeded the birth rate by 260 percent, with average life expectancy at a mere 42 years for men and 47 for women.
The world's largest heavy metals smelting complex was originally founded by the Soviets as a slave labor camp in Norilsk, Siberia. The snow in the area is jet black, the air is thick with the disgusting taste of sulfur and factory workers die 10 year sooner than the Russian average. Children continue to suffer with respiratory diseases and die at an alarming rate. Time Magazine reported "Within 30 miles (48 km) of the nickel smelter there's not a single living tree, it's just a wasteland."
Sumgayit was another important Soviet industrial center for producing agricultural and industrial chemicals. 70,000 to 120,000 tons of harmful emissions were released here annually. To this day, the percentage of babies born premature, stillborn, and with genetic defects is staggeringly high.
It’s hard to imagine how any of this ecocide could create a communist utopia, and I wonder if Lenin even fully understood what he was unleashing on the world when he put his plans for industrialization into motion.
Lenin led the Red Terror, a program of Bolshevik terror against all opponents of his dictatorship, including those mentioned earlier. In the face of a third mass revolt of the Russians against a ruler; this time Lenin, his direct orders were to "introduce mass terror" to the population. He gave some of these orders from his hospital bed after an assassination attempt which the party used as pretext to excuse these brutal policies.
The execution methods during Lenin's Red Terror were incredibly brutal, for example: Cages of rats tied to victim's bodies and exposed to flame so the rats would gnaw their way through the victim to escape, and victims slowly fed foot-first into furnaces: 
“Certain Chekas specialised in particular lines of torment: The Kharkov Cheka went in for scalping and hand-flaying; some of the Voronezh Checka's victims were thrust naked into an internally nail-studded barrel and were rolled around in it; others had their forehead branded with a five pointed star, whilst members of the clergy were 'crowned' with barbed wire; the Poltava and Kremenchug Chekas specialised in impaling the clergy (eighteen monks were impaled on a single day); also in Kremenchug, rebelling peasants were buried alive; at Watering-hole victims were crucified or stoned to death, whilst at Tsaritsyn their bones were sawn through; the Cheka of Odessa put officers to death by chaining them to planks and then pushing them very slowly into furnaces, or else by immersion first in a tank of boiling water, then into the cold sea, and then again exposing them to extreme heat; at Armavir, the 'death wreath' was used to apply increasing constriction to victims' heads; in Orel and elsewhere water was poured on naked prisoners in the winter-bound streets until they became living statues of ice; in Kiev the living would be buried for half an hour in a coffin containing a decomposing body; also in Kiev, the imaginative Chinese Cheka detachment amused itself by putting a rat into an iron tube sealed with wire netting at one end, the other end being placed against the victim's body, and the tube heated until the maddened rat, in an effort to escape, gnawed its way into the prisoner's guts. Johnson, the negro executioner at the Odessa Cheka, achieved special notoriety: he sometimes skinned his victims before killing them; after Odessa fell to the Whites in August 1919, he was caught and lynched by an angry mob. Women executioners could be crueler than men: Vera Grebeniukova, known as 'Dora', a beautiful young girl who was a colonel's daughter and a Chekist's lover, was reputed to have shot 700 prisoners during her two-and-a-half months' service with the Odessa Cheka.”
“The Chekas did not spare women and children. There are accounts of women being tortured and raped before being shot, wives of prisoners were sometimes blackmailed into sexual submission to Chekists. There were many cases of children between the ages of 8 and 16 being imprisoned; some were executed. The Chekas were occasionally honest enough to admit that they practised torture: in February 1920, such an admission was made by the Saratov Provincial Cheka at a meeting of the Saratov Soviet, and appeared in the press.”
In 1918, Lenin wrote to G. F. Fyodorov, ordering a massacre of sex workers in which hundreds were killed: 
"Appoint three men with dictatorial powers (yourself, Markin and one other), organise immediately mass terror, shoot and deport the hundreds of prostitutes who are making drunkards of the soldiers, former officers and the like. Not a minute of delay."
Lenin was an oppressor of the peasants and working classes, a despot, and, by 1918, the victorious enemy of the Russian revolution. A true counter-revolutionary. Which isn't too surprising, considering his bourgeois background and trade as a lawyer. He perfectly met the Marxist definition of a reactionary, yet tankies hold him up as the father of their "Marxist-Leninist" ideology and praise him as a great communist.
Lenin's acts later inspired further dictators in the 20th century who also misused the word "communism" to describe their brutal state-capitalist regimes. He effectively destroyed any chance humanity had to achieve communism in that century, and the damage he did to revolutionary action is still being felt today as the word "communism" has become synonymous with "totalitarian state" in the public consciousness.
Driven by the Taste of Boot
Regardless of the fact that "communism" actually means "a stateless, classless, moneyless society with common ownership of the means of production", Marxist-Leninists support state-capitalist regimes that use money issued by the state and have a ruling class of party elites that control the means of production and enjoy extreme privileges compared to the average workers. Tankies claim that these hierarchical, oppressive regimes will somehow bring about communism at a later date.
Tankies also adore Lenin's even-more-brutal successor Stalin, and see nothing wrong with the fact that Stalin sent other communists, anarchists, gay people  and basically anyone that annoyed him or one of his cronies to death camps. Homophobia was strongly ingrained in the culture of Stalin's USSR, with anyone seen as anything less than hyper-masculine in constant danger of being beat to death in his gulags:
”Passive homosexuals are not necessarily prisoners with gay inclinations, they are the unassertive, the timid, those who have lost a game of cards, those who have broken the camp code of ethics. Once you have the reputation of being a “cock”, it is impossible to get rid of it. It follows you from camp to camp. And if, after transfer to a new place a “fallen” prisoner fails to reveal himself, sooner or later it is bound to come to light. Then punishment is unavoidable, and it will take the form of a collective reprisal often ending in death.” 
They celebrate Mao's "cultural revolution" and its murderous witch-hunts against supposed 'reactionaries' who had the wrong haircut, wore makeup, happened to own a cat, write anti-authoritarian literature or have furniture in their home. Following in Stalin's footsteps, Mao criminalized homosexuality and anyone suspected of the "crime" was arrested. Castro did the same thing in Cuba.
A lot of tankies defend the many atrocities of the DPRK dictatorship; essentially a monarchy where the ruler inherits his position from his father. Tankies will tell you with a straight face that this monarchy is somehow a path to communism. They defend modern-day China's brutal oppression of its citizens, the use of deadly force to suppress democracy and quash protests, China's overseas colonialism and territory expansion, its concentration camps for minorities and organized destruction of the environment for short-term profit.
When people bring up anarchists in relation to tankies, it's because Anarchists particularly dislike the authoritarian regimes defended and idealized by tankies due to appalling events such as the Kronstadt rebellion, or the May Days in Spain. Anarchists are staunchly opposed to hierarchy, authority, rulers, states and capitalism. All things that tankies enthusiastically embrace.
Tankies often preach "left unity" to encourage all leftists to aid their supposed revolution. But throughout history, once they succeed in seizing power by taking control of the state and replacing the government figures with their party members, they immediately begin labeling anyone who isn't toeing their vanguard party line as a "revisionist", or a "counter-revolutionary"; sending all dissenters (especially anarchists) to labor camps, or simply executing them and dumping their bodies in mass graves. These purges always follow a Marxist-Leninist revolution and anarchists are usually the ones first up on the chopping block.
A tankie is anyone who presents themselves as a 'communist', but engages in apologism for torture, slavery, imprisonment, imperialism, capitalism, genocide and the erasure of actual left-wing movements. A tankie is anyone that claims communism can be achieved by replacing a state with another state. A tankie is anyone that will swear up and down that state-capitalism, dictator personality cults and ecosystem-destroying mass-industry will eventually lead to communism through the "withering away" of the brutal state that they uphold.
Any attempt at comradeship with a tankie is doomed to fail. Regardless of what they claim, tankies aren't interested in any form of debate, compromise, or exchange of ideas with anarchists or communists. Their only goal is to give their dangerous ideology an appearance of legitimacy. To wrongly represent it as a legit form of communism so they may further pollute radical politics with their tyrannical capitalist cult.
Anarchy is pure anathema to the tankie. We espouse opposition to authoritarianism, hierarchy, bureaucracy, state-sanctioned violence, prisons, worker exploitation, ecosystem destruction, state-capitalism and imperialism. This makes us, to the tankie, "reactionary counter-revolutionary imperialist scum". Doublespeak like this is one of their defining traits.
Behind closed doors, they see us as a threat to their plans for strongman dictatorships, cults of personality, mega-industrial capitalism and gulags as far as the eye can see. We are vermin to the tankie; fit only to be ridiculed and then swiftly exterminated once they seize power. Anarchy is their absolute worst fear. Anarchists are the biggest threat to their plans for party dictatorship.
They latch onto our movements and gradually corrupt them with their reactionary rhetoric and divide-and-conquer tactics. Their goals aren't even slightly aligned with ours, but they use shame and cries of victimization to squirrel themselves into our spaces. Their demands for 'left unity' and an end to 'divisiveness' and ‘sectarianism’ are obvious wolves in sheep's clothing and should be rejected outright.
We can't lose sight of the historical fact that genocide, nationalism, capitalism, bigotry, imperialism, struggle sessions and mass incarceration are some of the central tenets of Marxist-Leninist-Maoist practice, and whether they admit it publicly or not, something all tankies believe is necessary to ensure their vanguard's dictatorship and cement their own power on the party hierarchy.
Their only purpose in engaging you is to normalize their toxic beliefs and make us accepting of their presence in radical groups so they can grow their ranks. If you welcome tankies into your spaces, if you engage tankies in civil discourse, if you entertain their repugnant ideas or buy into their absurd notions of "left unity" and enable their attempts to create divisions between anarchists and sow discord, then they have already succeeded in poisoning your movement and rendering it useless.
 James E. Thorold Rogers, Six Centuries of Work and Wages (London: Allen and Unwin, 1949), pages 542-43.  “The Continuous Working Week in Soviet Russia,” International Labour Review, vol. 23, no. 2, February 1931.  Sabol, Steven (2017). "The Touch of Civilization": Comparing American and Russian Internal Colonization. University Press of Colorado. p. 47. ISBN 9781607325505  Lenin's Collected Works Vol. 27, p. 293.  Leggett, George (1986). The Cheka: Lenin's Political Police. Oxford University Press. ISBN 0-19-822862-7, pages 197 and 198.  Lenin Collected Works, Progress Publishers, , Moscow, Volume 35, page 349.  The Mordovian Marathon (Jerusalem, 1979).  Notes of a dissident (Ann Arbor, 1982).