Stop jumping to conclusions. Linus reacted to a troll comment that was later deleted. Something along the lines of "What, your shit don't stink?". It deserved the moron reply. Stop jumping to conclusions rather.
sure, that's absolutist and not always the best response, but not feeding trolls is a tenet of most successful online communities.
I have a ton of respect for Linus Torvalds' technical abilities, and for his way of succinctly and clearly explaining what can often be difficult concepts. However, his off-the-bat lack of civility -- hell, active hostility -- disgusts me sometimes. I'm sure he doesn't care, though: as he said, he's managed to accomplish his goals on the internet just fine how he is. So that's fine, I suppose. I just find it disappointing.
At any rate, there are plenty of examples (no links offhand, but I imagine they're fairly easily googlable if you're curious) of lkmk exchanges where Torvalds is flat out rude to people who are clearly wrong, but, from what I can tell, at least behaving civilly up to the point Torvalds blasts them.
Regardless, though, I still would argue that even in the face of an idiot slinging insults for no reason, "you're an idiot" is a waste of energy and not particularly respect-worthy. Don't feed the trolls.
There's also another attribute of the smartest people I know: they tend to interpret other's responses given the most intelligent interpretation possible.
In the case of some, though, complete neutrality is the best one can do.
Actually, it makes sense in context to most native English speakers. "To reply in kind," is an oft used idiom. In this phrase "kind" is a synonym for type. It is to say, "to reply in the same way." (Usually in a way which is not kind in the kindness sense.)
http://dictionary.reference.com/browse/retort
I would agree, however, that one, "has no obligation to react to idiotic comments in kind." I hope I've succeeded.