It's Because He's Black…

No, it's not because he supported McCain in the primaries

No, not Barack Obama, but rather Arizona legislative district 20 Republican Party chairman Anthony Miller, who has been harassed by the teabeggers and has resigned:

A nasty battle between factions of Legislative District 20 Republicans and fears that it could turn violent in the wake of what happened in Tucson on Saturday prompted District Chairman Anthony Miller and several others to resign.

Miller, a 43-year-old Ahwatukee Foothills resident and former campaign worker for U.S. Sen. John McCain, was re-elected to a second one-year term last month. He said
constant verbal attacks after that election and Internet blog posts by some local members with Tea Party ties made him worry about his family's safety.

People are not upset at him because he supported McCain, who, after all demolished J.D. Hayworth in the primary, so he had broad based support from the party.

The problem here is that the Teabaggers think that his skin color clashes with the Arizona Republican Party, though they probably use a 2 word phrase beginning with "uppity".