Don't confuse him with facts, he's really struggling to understand this concept.
White racists are a large part of the Republican coalition. It is essentially made up of said racists, religious conservatives, libertarians, and the country club/RINO crowd. White racists don't vote Democrat because they see it as the party of blacks, although they'll switch in a heartbeat to vote against a Republican of color (Bobby Jindal) or keep Kleagle Byrd in office. Those statistics about voting less for black Democrats among white Democrats doesn't take into account legitimate reasons to not vote for those candidates (Cynthia McKinney, Kweisi Mfume, William Jefferson).