Mastodon is designed around the idea that if someone asks to hear what you have to say, your and/or their instance administrator should decide whether you get to hear it or not. If one Mastodon instance blocks another, users on the blocking server cannot see anyone on the other server. If the admin decides to "mute" the other instance, then people on their instance can see content that they explicitly subscribe to, but nobody else is told about it (normally, if someone follows you and you "boost" another post, the person following you sees what you boosted...but if the boost is of something by someone on a muted instance, nobody else sees). But the admin doesn't have to mute--they can block, and then you can't follow the person at all (without switching to another instance yourself).

So it's the same story. It's just distributed third-party censorship instead of centralized third-party censorship...which actually is less bad, I think, but the idea is certainly not that you can ask to hear what someone has to say.

Anyway, the granularity of full-featured freedom for Mastodon is at the instance level, not the user level.