they can help counter pro-capitalism ideologues

Only with authoritarian ideals, and while supporting places like China and N. Korea, giving capitalists every reason to mock what the tankies falsely present as communism.

Like, you do you, but personally simply having anti-capitalism in common isn’t enough to overlook the oppressive ideas they preach and support (even if indirectly, by using that instance specifically, they actively endorse and condone those ideals), just like having anti-stateism in common isn’t enough to overlook the oppressive ideas "an"caps preach and support.

They’re telling you who they are, the best thing you can do is listen (and if any of these users really are that chill and not at all tankies like you give them credit for, they should understand why being affiliated with authoritarians is a red flag to most users, and have no problem creating an account on another instance that isn’t bringing mass defederation on to itself by brigading and harassing anyone who doesn’t agree with their oppressive views)