Aside from the fact that you're isolating a quote out of context, I think you're wrong. I won't speak for Mr. Chomsky, but personally, I don't get angry with people because I'm pretty sure I'm right about everything (I know I'm not), but because I'm pretty sure that they're wrong. It's a very different reason, and I think it is wholly legitimate to be upset by people who are insistent about their ignorance and stupidity.