If your instance of choice has “hard blacklisted”/defederated another instance, you can’t see or interact with said instance at all. And if you choose to join a instance that refuses to defederate from any other instance, chances are that said instance is heavily defederated from other popular instances unless it’s very small or you selfhost it yourself. I don’t really bother with mastodon precisely for these reasons, it’s very hard to have actual control, and it’s very easy to get arbitrarily locked out of the ecosystem.
Doesn’t matter if you want to call this censorship or not, fact is that there isn’t really a lot of freedom with mastodon, pleroma etc, due to how the fediverse has been structured. It’s better than traditional centralized social media but that’s not a very high bar.
