The fact its true makes no difference. Look at Huckabee supporters. The guy has lied openly, he has changed positions during his campaign, he makes stupid Jesse Jackson like remarks (I didn't raise taxes, I raised hope, stand for something or fall for anything, an Aaron Tippen song actually, and many more) but when he is attacked for his emptiness or ridiculousness or even his policies, the ardent supporters see that as a personal attack on a great and faithful man and maybe even an attack on Christianity itself.
The same probably goes for Obama supporters but to a greater level and to a wider array of people. Its obvious Obama is an empty suit whose speeches are just words without substance but don't tell his followers (not supporters).