This isn't true at all. Most famous black athletes who make their views known are Democrats. Maybe the 10-15% are Republicans.
http://sunlightfoundation.com/blog/2010/10/12/nba-stars-contributed-to-democrats-in-2008-obama-looks-to-raise-money-with-them-in-2010/Nine players, six whom also contributed to the Obama campaign, contributed to the DNC. These players included some of the biggest stars in the league including LeBron James, Dwight Howard, Rashard Lewis, Emeka Okafor and Baron Davis.
http://espn.go.com/blog/truehoop/post/_/id/1257/the-democrats-and-republicans-of-the-nbaExclusively Democratic Giving
Kareem Abdul-Jabbar $1,000
Charles Barkley $2,000
Jeanie Buss $5,000
Phil Jackson $5,455
Michael Jordan $18,000
Alonzo Mourning $25,000
Gregg Popovich $2,000
Pat Riley $4,754
David Stern $781,780
Isiah Thomas $5,000
Majority Democratic Giving
George Karl $7,000
Jerry Reinsdorf $346,278
Julius 'Dr. J' Erving $2,300
Playing the Middle
Mark Cuban $7,000
Majority Republican Giving
Jerry Buss $23,550
Exclusively Republican Giving
Richard DeVos $2,866,88 (76% to special interests--24% to Republicans)
Clyde Drexler $2,000
Karl Malone $10,000
