Ultimately, you did the right thing. Blithering on about the "right" way to teach history will make class drag, will make your teacher dislike you, will make your classmates dislike you, might make you feel like a jackass, and probably won't teach any of your friends anything that they want or care to know, and if they care and you care, you could always talk about it outside of class. It might piss you off about how SOMEBODY DID SOMETHING WRONG but hey, that's life.
Much better to take out your frustrations with that crap on the Internet, where you get postcount for telling people that they're wrong and where they miiiiight actually give a damn. Even if they don't, well, they're just people on the Internet.