I don't think he does
I think he just wants Hillary to be the nominee so badly that the negatives Obama clearly has (which in my mind pale in comparison to Senator Clinton's) are greatly reinforced. I think it's very understandable and very much a human trait to do that. I'm probably just as guilty with some of my views towards Hillary and McCain. They're both an obstacle to the guy I want to win and so my hearing tends to be a bit selective.
Art
