But even in the more generic sense -- they can't disconnect you, they can disconnect the account you have on their server -- and it's common practice for people to have alts on different ones just for different topics they post about.
Lots of speech is definitely not up to my clearly incredible and most certainly correct intelligence level and should be blocked!
/s
See:
> they can't disconnect you, they can disconnect the account you have on their server
There's nothing stopping you from having an alt on a different server that does connect to fascism.social or what-have-you, and the apps these days are pretty good about switching among alts so the UX isn't bad. I will also note, the "stories here" tend to focus on corner cases: instance blocking is predominantly reactive (with Gab being the big exception) and you can always just run your own instance if you want to control your own moderation. I run my own and haven't had any problems with instance blocking.
And again -- if you do end up on a server that implements a block you don't like, you can just move (which transfers your followers) https://docs.joinmastodon.org/user/moving/#move
Some people (notably, it seems, Eugen) think "the point" of federation is to provide a seamless Twitter-like global experience that just happens to be hosted modularly. A lot of the current site culture prefers to consider each instance like a little neighborhood, with federation augmenting a local-first experience. (Conflict over product vision ensues.)
But really, no matter what you're looking for, the vast majority of the time you can just use whatever instance and it's fine -- mod drama whole-instance-blocks get a lot of attention, but it's way more of a problem in theory than in practice (especially now you can move your followers if you move instances).
The ActivityPub protocol itself makes it very simple to keep activities out of the public view. It's Mastodon, and projects that implement AP as a compatibility layer with it that address everything as public.