Ignorance. To me, it's perfectly okay to not know about something, and make a mistake because of it. Even if it's someone's fault for not looking at a bunch of cultures/points of views and then talking about it, it's not that big of a deal. HOWEVER, when someone refuses to listen to another point of view from someone else highly educated on the subject, THAT'S where we have a problem.
For example, the other day a girl said that Paganism is a cult. Cult is a derogatory term, and most certainly does not apply to Paganism. It's not an opinion, it's a fact. When I tried to explain to her that it really isn't, and why, she still told me that Paga