> Lets suppose they can censor IP and DNS. From what I see, nostr already addresses this risk with its architecture.

Nostr addresses censorship by relays themselves. But if all involved organizations wanted it, and it's a closed market, they could censor all DNS names and IP addresses used by Nostr relays.
Obviously this is hard and unlikely, which is why Nostr does provide (some level of) censorship resistance.

> What is the underlying problem that nostr needs to solve? What are the requirements to that solution?

From my understanding it's corporate censorship and it mostly does solve that.

> I see nostr's primary aim is to enable uncensorable communication with a minimalistic protocol design.

I agree. I never suggested allowing edits is against the purpose of Nostr.