In a less politically correct time they probably would have used a different word.
They call him a Muslim -- and are quite suddenly lashing out at "his people" almost a decade after 9/11--- simply because they aren't allowed to call him what they want to call him. Sure, they don't think Muslims are American. They also don't think liberals are American, blacks are American, Mexicans are America, gays are American, atheists are American or anyone else who doesn't identify themselves explicitly with them are American. They are, you see, Real America. Everyone else is not.
This stuff is like water --- it always finds a way to seep out. Calling Obama a Muslim is just a convenient way of justifying their existing bigotry toward everything he actually is. It's not really all that complicated.
She's right, but it actually is more complicated than that: as long as The Haters' attention is misdirected to focus on Obama, Pelosi, Reid, liberals, gays, Mexicans, and blacks, it's not focused on their real enemies who are working them like a rented mule.