burntheartist, I'd be worried to be near you in real life. If I happened not to have learned something in history class, you might punch me in the back of the head. Do you really think that educating people by violence will actually get anything done other than having everyone be pissed off at you? You'd get your ass kicked the first time you picked on someone who actually knew some self-defense.
On a less vitriolic note, the reason I think people get so pissed off about ignorance is because it's so easy to obtain information these days. I don't like it either, but most people would rather you Googled something than asked them the question -- I guess they see it as wasted breath or something. Whenever I don't know something, people deliberately don't answer me, and direct me to Google.
So the undercurrent is, if you don't know something, you should. Go look it up on Google. It's cake to obtain information now, and thus it is perceived that there is no excuse for not knowing something.