It would defeat the purpose of federation if there's a different server for each political persuasion. Why bother with federation if you don't want to see anything you disagree with? Each server would be its own hugbox.
What do you think the purpose of federation is? I like federation because I can choose a server I like or run my own and still talk to people on other servers.
That's kind of my point. You end up with the option of 1) it's centralized. Everyone only cares about who Mastodon.social federates with. How it's built to work doesn't actually matter. 2) It's centralized. Users wrestle control from Mastodon.social and everyone cares about who some other server federates with. 3) It's a balkanized mess. You spend all your time worrying about who you're federated with so that your content and the content you want to see become accessible. 4) It's decentralized, but nobody really bothers with banning anyone anyway, because it leads to the other scenarios and they are worse.