[JulianMorrison]

The way it works in Mastodon is that (1) not everyone runs a node, but there are many nodes, and they each have their own policies and can kick users off, and (2) nodes can blacklist other nodes they federate content from.

This two level split allows node operators to think of most other users at the node level, which means dealing with far fewer entities. It provides users with a choice of hosts, but means that their choice has consequences.