What you describe is exactly the type of censorship Nostr was designed to thwart.
"But as soon as it becomes offensive"… Who defines "offensive"? Whoever tries to define that term definitively is practicing censorship.
My existence is offensive to some people. So I ask again - who's going to set the standard for what's offensive?
Nostr is a big tent which will eventually have a lot of diverse people using it. The approach we need to take is one of "how can we all just get along?" Objectively defining the content (even in broad terms) and then filtering on those definitions is the only viable solution I see at this point. And it's culturally neutral.
But no one gets to be "the censor of Nostr". No one gets to put someone else in a digital ghetto. That's not what Nostr is about. If that's what you what I'd suggest you go use Twitter, FB, Insta or even Mastodon. They work on the exact model you describe.