I saw an interview a couple of years back with Sean Connery who proudly proclaimed that what bugged him the most about people was stupidity. This he could not abide, this he could not stay quiet about.
Um, aren't we all born starting at zero? And aren't we all raised in different environments, nay worlds? How can you hold everyone up to the same "intelligence" standard as yourself if the person didn't run the same course? (And maybe didn't start with the same model of equipment.)
I can remember many times in my life being mocked for my lack of knowledge in a certain arena. Now, I think this just reflects poorly on the "mocker", though at the time I wasn't smart enough to avoid feeling shitty about myself.
There was the time I was mocked for not knowing fashion when I switched from private (uniform wearing) school to public school in the 7th grade. There was the time I was mocked for talking in a bathhouse (during my first visit). There has been mocking for a lack of band and musician knowledge, mocking for my "taste" in things, mocking, mocking and mocking. (I like that word, can you tell?)
When people criticize or feel ill will toward others due to "stupidity", this is judgemental behaviour that helps no one. Be charitable and help someone learn something new, or laugh derisively at the person to make them feel like shit? Which one do you choose? If it's the latter, why the hell are you so stupid?