One thing is that capitalism is poorly defined. Is it markets? Is it companies over some certain arbitrary size? Is it private ownership of the means of production, like Marx said, and if so how do you define "means of production"?
I think when people say they're anti-capitalist, what they usually mean is they're unhappy with the system and find private actors to be the most destructive actors, at least currently in their home location.
PS, lemmy.ml stands for lemmy.marxist-leninist. The instance has seemed mostly general audience since I joined after the Reddit blackout, but it is run by communists.