Further, once you pick a server, if you are kicked off, you lose all your followers because they are following you@thatserver which you cannot get onto anymore.
This seems obvious to me as a necessary feature...?
https://github.com/mastodon/mastodon/issues/3796 https://github.com/mastodon/mastodon/issues/2668
Being able to choose which other servers your server federates with is a feature, not a bug.
> you lose all your followers because they are following you@thatserver which you cannot get onto anymore.
Not true as of recent (May 2022 or so) versions of Mastodon.
Most do, the default is open federation.
> As I recall, most servers would not talk to gab's servers.
It's hardly a surprise that most people don't want to associate with neo-Nazis and others with similar worthless ideologies.
The fact that admins can firewall off instances if they're are run by arseholes is a good thing.
I would flip what you just said on its head and say practically the opposite: the virtue of Mastodon is that when the Nazis seize power not all instances will be forced to censor Jews (whereas Twitter will be forced to do it or shut down).
For a server to operate you only need a very basic power source and internet connection, even in an occupied country it seems plenty doable.
Sure someone can set up a server somewhere and publish whatever they want but if no one reads it it won't really matter. Most people won't change where they get their news overnight even if the government does impose censorship. That's why federated social media is so valuable, widespread use of it ASAP is a benefit to society. It can de-concentrate the ownership of media distribution, decentralize control and make the next Office of Censorship's job much harder.