This topic has been brought up before, and it should again because it's important.

First of all, I would define, "can" here as having access to circumstances that would allow someone to live a vegan lifestyle while being reasonably healthy. If you wouldn't be able to afford enough food to be healthy, have a medical condition which would make a vegan lifestyle unfeasible, etc. then I'm not talking about you. However, I'd say that almost everyone could make a few accommodations to live a less speciesist life.

Secondly, I do acknowledge that systemic change is way more effective and important than individual choices. However, one can and should strive for both. There is no ethical consumption under capitalism, but that doesn't mean all consumption and other interactions with the system carry even remotely the same ethical weight. We need to attack the status quo directly on a large scale to make truly meaningful change, but right now there are changes you can make in how you do things.

The personhood of non-humans is unambiguous. It's not a matter of debate within the context of anarchism anymore than the personhood of any human marginalized groups. By accepting non-human personhood, the enormity of the crimes being committed against people based on their species is horrific beyond compare especially contrasted against how normalized the process is. Vegans are often considered finicky, preachy, etc. but understand that when we see a steak, we see it outside of the anthropocentric context.

We don't see food, we see someone's corpse. A unique individual that was imprisoned and murdered for the consumption of their oppressors. It's not a matter of personal choice or perspective, it's the result of domination, aggression, and oppression under a consistent application of that term. An anarchist should realize this and willingly abstain just from sheer repulsion, much less the ethics involved. If it were human lives being put under that kind of cruelty, then the anarchist community would immediately exclude anyone who willingly participated in it.

Veganism is a lot more than the animal product industry, of course. However, the fact that many anarchists aren't evil willing to stop devouring someone's dead body, that they can still find it even slightly appealing says that they need to reexamine who they consider people worthy of liberation.

All people are equal, this is a fact. Regardless of species. This doesn't mean that all non-humans have the same level of personhood, I'm largely talking about the animals that are usually consumed such as chickens, cows, pigs, deer, etc. that unambiguously feel pain and have enough agency to be considered people.

If you'd say that an anarchist would have a moral obligation to defend or refuse to participate in the oppression a targeted human group in a fascist dictatorship, even if it meant being publicly beaten/executed then applying a similar duty consistently would mean that you should sacrifice for the non-human targeted groups as well. The fact is, the crimes being perpetrated against non-humans exceeds anything that is currently being done to humans. Trillions of lives a year are involved compared to mere billions.

That doesn't mean I don't fight for human liberation, but non-human liberation must be taken just as seriously.