@tedvim individual users actually can effectively silence servers. On the web interface, it's in the three dots at the bottom right of each post (except the ones on your own instance, of course - you cannot block your own server). Click "Hide everything from example.com" and you achieve the desired effect.
What you cannot do is *undo* a silence that the instance admin put on. I wish for a feature that says, "Allow me to interact with users at example.com in spite of the ban. I am an adult with a thick skin. If the users at example.com are mean to me, I promise not to go crying to my admin, because he doesn't want to deal with their crap."
@khird That, indeed, would be an amazing feature. It's kind of weird that the whole instance blocking thing is framed as freedom to not get certain crap. Silencing some servers by default, with effect in some places like hashtag search, is a very sensible thing to do for admins that want to promote certain experience. But imposing wide blocks and pressing all servers to apply the same restrictions is a failure of the federation model.