Not voting, owning property, eating meat, abusing workers, etc. can all be justified under the "no ethical consumption under capitalism" mantra. And while this is true, it's ridiculous to pretend that the present suffering of living beings does not influence our decision-making. Communists who throw up this platitude in defense of their actions is the equivalent of "Well that's just my opinion", to defend awful political views, "Well we can't change the past why complain," to justify past action, or any other over-used line to shed responsibility.
We have the ability to mitigate the suffering of others on our path to communism. Likewise, it's our role to point out that reformism won't end capitalism. But if your only goal is to end capitalism, and not to end suffering, present and future, then why the fuck are you even communist?
So next time someone asks why you purchase x, or eat x, don't get defensive. Accept that you, like everyone, myself included, contributes to global suffering willingly. And maybe consider doing something about that. And obviously if someones bein a dick about it, it's whatever. But "no ethical consumption" does not shield you from criticism.