Not practical to issue notices to every relay operator. Centralized corporations make 1000x easier targets.
Discussion
issuing a notice is very easy, so is canceling a domain registration
Issuing demands to the 500 relay hosts and pursuing domain cancellations is an insanely high bar vs issuing a single letter to Twitter corporate headquarters. That isn’t even taking into consideration private relays or the fact that Nostr is open source and will improve. Nostr isn’t perfect but its design makes it 1000x harder to effectively censor.