This causes massive compassion fatigue. Take that into account, and it becomes clear that Linus is not as big an asshole as you think.
Of all the arguments for being brusque on the web, this is the one I find most unappealing... as well as the least applicable for the matter at hand.
As far as I can tell, there's nothing about Linus' reply that depended on his admittedly high level of technical competence. In fact, it seemed he was saying "don't rely on being technically correct, consider the consequences"... in a way that got people's attention.
"I'm smart, so it's OK to an asshole" is about as shitty as an attitude as "not my problem, I'm just going by specs" - in fact, it's kind of similar. ... I bet all the up-voters thought they were the "highly technically proficient people"!
In general, sites like Hackernews or Stackoverflow wouldn't work at all if smart people couldn't handle answering basic questions without being jerks.
For every Steve Wozniak there is a Steve Jobs.
They being so damn smart does not give them the right to be condescending and insult people who can't keep up. So I'm not as smart as he is, does that make invaluable? Does that give him the right to call me stupid? What if I am doing my best? If my best try isn't really helping, then they should simply ignore me, not attack me. Nothing gives anybody the right to insult people.
It's the guiding principle here on HN: be civil. Just like others need to polish their technical abilities, being nice is something they should work on.