We can't do anything about it when and if those nasty people come to Nostr. Censorship resistant technology works for both good people and bad people.
Discussion
To sharpen the adversarial thinking a bit… If people explore Nostr using large relays, malicious noters can get those relays into trouble with illegal content, right? But, if Nostr were instead made up of lots of small, highly permissioned relays “for me and my buddies,” search and discovery would be much harder, right?
Forgive my nontechnical speak, and feel free to sharpen this further if I’m not understanding well.