Because liberals see everything through the prism of race, they assume everyone else does too. My opposition to Obama has nothing to do with his skin color; it has to do with his idiotic policies. I would be just as strongly opposed to him if he was a blonde, blue-eyed WASP.
I'd also vote for Thomas Sowell or Allen West over John Kerry or Hillary or even Mitt Romney for that matter. Race has nothing to do with it--it is based solely on ideas.
What could be more racist than supporting someone based solely on race? I love Samuel L. Jackson as an actor, but like most of them, he's an idiot.