I've covered some of the points about anti-capitalism in the reply I just wrote for a similar post, so I'll link there to avoid redundancy.

I don't really understand the intended message with the Mastodon example. "Free speech" platforms are almost always swamped with neo-nazis, literal pedophiles and other super controversial people searching for sites to host their garbage whenever they get kicked from other places, and revolt most other people who would consider using the platform. This has nothing to do with the anti-capitalist and queer-only instances not wanting to host them, it would have happened even if those instances never existed. You might as well blame Beehaw for blocking the Trump fanatics and neo-Nazis who ended up populating Wolfballs. It doesn't make sense, they're not to blame. Almost any site bans those users, not just far-left, or even left, sites. Most centrists and almost any site with advertisers don't want to share space with Gab users screeching out edgy slurs and spam either. It's a basic expectation of being able to hold a productive conversation. Any community should be allowed to kick out anti-social invaders.

No, instances with basic standards kicking our hateful users isn't to blame for why general instances host them. It's the general instances that accepted them and didn't also say no. Those general instances were allowed to kick them out too, they chose not to. Most Lemmy instances historically have kicked them, even those run by liberal capitalists.

And if they allow they platform to be turned into a Nazi pub, they're certainly not being apolitical. Abstaining is a political decision. Trolley problem 101.

I'm fine with people not wanting to connect with instances filled with people who obsess about wanting to kill them. I don't see the issue here.

I do understand the value of exposing people to different to viewpoints, and the dangers of echo chambers, but there is a lot of space in-between complete isolation and letting everyone into everywhere. And I actually enjoy using separate communities for each. I was one of the few users who used the former Go Talk It Out (gtio.io) Lemmy instance, where any conversation was allowed provided it was good-faith and civil. There are some conversations where I do want a range of political opinions and where political opinions don't even matter, and others where I want to discuss a theoretical idea without unproductive spam from people who see a word and whine or troll. So I would rather see that system of federation, where instances specialise and choose who they link to appropriately.