Linus is very well known for his rants, but you've definitely mischaracterized them. He's seldom incoherent, and the ones that are vulgar enough to make for juicy sensationalized "news" are only ever directed at contributors who are experienced enough to know better than to break userspace or something badly wrong like that. His more level-headed corrections of well-meaning inexperienced developers don't make the news.
I'm not seeing where the ire was directed at anybody new. The two messages Linus sent were in reply to a pull request from Dave Airlie, a very high-level and extremely experienced developer. Daniel Vetter tried to chastise Linus for chewing out some new contributor named Noralf, but it appears that the real problem is that the problems with Noralf's code went unfixed by intermediaries like Vetter and Airlie and made it all the way to Linus.
The kernel shouldn't let bad code into the tree just because the author is inexperienced. Subsystem maintainers are supposed to be a very thorough filter, so that the patches reaching Linus are up to standard. When bad code makes it to Linus, it's his job to complain about it. And based on that thread, it looks like he was complaining about it, and was not directing the complaints at the original author but at the people who were responsible for reviewing and testing the code.
To me it reads like redirecting blame to the contributor by appearing to "defend" him. Linus was obviously replying (and chastising) the person who sent him the code, and who was supposed to review it beforehand, not the original author.
