Sometimes the truth hurts and it's useful to have offensive people saying it out loud. 

Sometimes saying the truth is not useful. In that case I would call it impolite, but not wrong.

And sometimes offense things are just wrong or at least founded on junk science. Fortunately we don't have an algorithm here to boost that latter category disproportionately, but people have made entire careers out of a they-don't-let-me-say-this Schpiel. Social media algorithms love that, hopefully Nostr doesn't amplify it.

Right to speak goes without saying.