Look at his comment in the same thread: https://github.com/torvalds/linux/pull/17#issuecomment-56599...
He says: "Btw, Joseph, you're a quality example of why I detest the github interface. For some reason, github has attracted people who have zero taste, don't care about commit logs, and can't be bothered. The fact that I have higher standards then makes people like you make snarky comments, thinking that you are cool. You're a moron. Linus"
If you say something stupid or do anything wrong, they will hate for for it and call you an idiot.
It's not necessarily a bad thing. I guess it may help prevent lesser programmers from contributing code to the kernal.
Here is the example sentence in standard hacker rudeness scale:
0. Please fix this.
1. Fix this now, you moron. <-- Linus
2. I guess, we don't use this until you find way to fix this. Maybe I help with FreeBSD project meanwhile.
3. I need you to fix this NOW.
4. I NEED TO YOU TO FIX THIS NOW!
5. I NEED YOU TO FIX THIS NOW, MORON!
Why should we not spit on people who don't care about commit logs. When Linus is insulting person, that stings a while. Shitty developer is insulting and harassing everyone day by day.
Being honest and aggressive is way to get people change their behavior or leave.
I'm not saying that Linus is right here. I'm just pointing out that rudeness can be the right way to deal with people who don't take a hint.