While I can't speak for anyone else, I dislike them because that arrogant asshat Serj can't seem to shut his unwashed hippie mouth about politics and stick to music, one of the few things he's good at. It's totally cool to slam the US Government but if you assume we all support it, and you pick on the people who oppose it you're going to get your Armenian ass handed to you.
He also shills for PETA which makes him a pinhead.