This touches an interesting point. Feedback must be accurate. If you are actually provably wrong, I am not doing you a favor by telling you you that you are "not right". Losing face is a fact of life. When I'm wrong, I want to know I am wrong, what I am wrong about and just how wrong am I. If possible, tell me what can I do to be right the next time.
It must also be kind. You do not point someone is wrong to humiliate the person and you should take care not to (I try and I fail more often than I'd like to) fall into the trap of judging a person for his or her first efforts.
Having said that, I am almost sure all the exaggerated discourse on the Linux kernel mailing list is not really part of the message, but should be understood as more like a sport, a game, where the one with the most elaborately crafted insult wins. When Linus says you should be retroactively aborted he most likely wants to say you are very wrong and your idea is really bad and that, maybe, you should be more thorough the next time you submit a patch. Their time is a finite resource.
Is this the most efficient way to run the community? Probably not. We just don't know what is the most efficient way to do it and it can just be that Linus found a local maximum.