Earlier quoted context omitted.
>This is only true among mastodon servers that connect to each other. 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.
The problem with this idea is that if by some unfortunate accident of history, Nazis gain power again, they'll say exactly what you just said except replace the word Nazi with Jew. 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.