Right, it absolutely isn't. Some form of censorship is vital. This claim becomes more agreeable when substituting "censorship" with the almost-synonymous word "moderation".
With nostr, your identity is just a pubkey, and you can publish to / read from several nodes simultaneously. So if some node refuses to puplish certain content, you can just get it from another node without having to create a whole new identity.
Bias and financial interests in speech and content are more rampant, now, than they have ever been. I don’t trust anyone but myself to “save” me from seeing what I can only describe as “wrongthink”.
https://www.newyorker.com/news/letter-from-silicon-valley/th...
Despite that, usernames and their corresponding IPs get blocked routinely and we still see spam regularly even if only for a brief time.
Any forum will have the same problem: get popular and whacking spammers becomes a full-time grind. Allow people to upload files and you’ll have the FBI asking why you’re facilitating transfer of pirated movies, CSAM, etc. Have the wrong people decide to use private messages and now the FBI is back asking if you knew they were planning terrorist attacks.
None of those are completely impossible, of course, but they end up being expensive and burning out volunteers. Limiting anonymity helps, but only so much - it’s just an expensive space to be in.