I think it's fine for communities which are created for specific political, social movements etc to do so. But when you get broader communities like this one, it's much more difficult and thorny to figure out. If you set up a socialist server, crack on with defederating from right-wing ones. If your server is about environmental activism, swing the banhammer on anyone who questions climate change. I legit have no problem with that.
I suspect there's very little disagreement about keeping The Donald types defederated and related /c/s banned. But that's only the easy edge of it.
Servers like this one need to be really careful we don't get whittled away by various niche groups demanding bans and defederations.
If a server allows conservative users, or people who think that sex-based rights are important, or that anti-Zionism is racism, etc etc etc. Do we ban them? Where do we draw that line?
Why don't we just keep it to Trump/MAGA servers, trolls and bot-farms, and communities which directly interfere with and undermine ours, or at least something in that ballpark?