This goes back to not voting in every election. Groups that invest (money, time, votes) on local races (city council, school board) have a greater variety to pick when one of these people goes on to higher office (state-level, county-level) and then goes on to federal office.
The primaries are already too late - it's all about the local races.
Realistically, whoever is the admin of the instance can decide to block another instance for any reason, or no reason at all. Admins of threadiverse sites are maintaining (and owning) these instances as a hobby. If they decide they don't want to look at content about penguins during their leisure time, they can just ... block them.
Since threadiverse is a bit less mature than the mastodon ecosystem, there aren't any "big" democratically owned and managed instances, so most people are stuck with benevolent dictator for life situations.
Edit: Also, if an admin doesn't want penguin content stored on their servers (which they pay for), it's a bit strange to say they must store content they don't like on what is essentially their personal machine.
thanks, found those. I guess blocking an entire instance is still WIP
noob question, but where is the block UI
if you're still on there, why would they leave?
Mastodon communities currently defederate from instances of over a certain size (including .social) because of how hard it is to moderate large instances, beehaw isn't doing anything weird in this case.