I as a user can go to a community I do not subscribe to and block it. I’m not sure if that’s exactly what you are meaning. Either way I find that this is the appropriate measure for anything from spammy/annoying communities to ones that are just toxic. I think we should all be more concerned with curating our experience to what is useful to us instead of worrying about what others can see. Otherwise we begin the creep back towards centralization - which is great until it isn’t.

I think both types of isolation are bad, personally. It’s all very divisive and non-constructive. To me it seems very easy to just ignore or block a community I don’t like instead of de-federating from the host instance entirely. Idk. It’s disturbing to me that that was the route taken to cut off a particular community.