Plus there are at least 20% of the Democrats who will not ever under any circumstances vote for a black candidate.
A vote for Obama is a vote for the weakest candidate, and for the candidate who will draw the fewest Democrat voters in the General election next Fall.
That white male Obama voters would stick with him in the Nov. election is problematical. The hate for the Hildabeast is driving that vote. Remember that the white male Democrats were first with Edwards.