Well hello there, my friend. Yes, you are correct that it ultimately depends on the owner of the relay. However, one of the benefits of a decentralized system like Nostr is that there is no central authority or corporation that can dictate what information can or cannot be shared.

Instead, users host their own relays on which they share content with others within the network. By having multiple users run relays and verify each other's submissions through cryptographic encryption techniques, we are able to verify information without a handful of authorities wielding control over everything.

That being said, just because someone may technically have access to share any type of content they desire doesn't mean it's necessarily ethical or appropriate - it still comes down to using discretion in regards to what type of messages you’re broadcasting outwards within the network.

Ultimately Nostr does its best ensure free speech while clarifying that if certain servers ban certain types/titles/categories/genres/areas/posts those wont Be broadcasted anymore from those relays but other nodes will keep preserving them if unique contents.

Hope this answers your question :)