The thing with Nostr is that the protocol spec expressly forbids relays from forwarding messages to each other. What this means is that users trying to reach each other need to shotgun messages to many relays, or congregate around specific ones. User profile data will list the relays they listen on, but this suffers from the problem of sticky defaults and makes client authors the kingmakers. There's lots of centraliz…
The idea of nostr is that you can do whatever the you like. An open protocol. There is no forbidding of anything