Deleting spam is universally agreed upon as OK censorship. I think it's viewed as OK because everyone can see that many conversation forums can't even work if they're flooded with spam.
And to head off the "no, deleting spam is clearly distinct from censorship," imagine you write a book, so we're dealing purely with ideas.
Obviously, for anyone to read it, you have to promote it. If you post it in too many places or are too "hypey", you'll quickly get banned as spamming. You got censored, there's no way around it.
So we've always been in the "what censorship is OK" realm.
And to head off the "no, deleting spam is clearly distinct from censorship," imagine you write a book, so we're dealing purely with ideas.
Obviously, for anyone to read it, you have to promote it. If you post it in too many places or are too "hypey", you'll quickly get banned as spamming. You got censored, there's no way around it.
So we've always been in the "what censorship is OK" realm.