The reason people like you hate her is that she is so often smart and exactly right.
People dislike her because she's a self-promoter who puts her personal interests of attention-seeking above her professional responsibilities of being a serious legislator. Then there's the fact that her public statements are so wildly off the mark and blatantly inaccurate to such a degree as to make a mockery of her status as an elected representative.
It wouldn't be that big of a deal if she was some kind of media personality since that seems to be the norm nowadays. But we understandably expect more from our elected officials. All Bachmann has managed to do is lower the professional standards of Congress which was already suffering low approval ratings.
My guess is that she's not at all respected or liked by even her own Republican colleagues, although it's doubtful that any of them would ever come out and say so.
But for some reason that frankly mystifies me, conservatives always fall in love with rhetorical bomb throwers. In that sense, Bachmann is like the attention-getting trash-talking player on the field who never makes any meaningful plays. But that doesn't matter to the drunk fans fans who just love all that verbal chest thumping and in-yer-face attitude.