You don’t want this - that’s fine, you can just block the instances you’d like to avoid, that’s one of the best features of the fediverse. But if someone else would like to see this content, why not give them such option? Why would you want to decide for the others? Let them make this decision.
I don’t understand what’s the big deal. If they join fediverse - cool, more content for us. If they decide to quit, how is it different from a regular instance defederating? Why people think that users would abandon fediverse just to follow them? I’m still new here but I’d say that if some community vanishes, I just search for another ones that are available here or just stay with those I already have. Maybe I just can’t see something but I left reddit because it decided to restrict its users, I thought the fediverse wouldn’t do the same.
I still prefer to write “Twitter” because fuck X and Musk