A reader points out:
"I have always been amused that Kanye West, the benign rapper with the art school background and the English professor mother, is the one into trendy political grandstanding and accusing Bush of not caring about black people, whereas 50 Cent, the gangsta rapper with the South Jamaica, Queens background and the cocaine-dealer mother, is the one who makes occasionally favorable references to Bush and doesn't think Katrina should be blamed on any people in particular."
He also points out that in 1972, another black celebrity endorsed Richard Nixon besides Sammy Davis Jr. (who agonized for rest of his life over whether he had betrayed his people) and Wilt Chamberlain (who did not): James Brown. You can't get any blacker culturally than Soul Brother Number One, so that gave Brown more freedom politically to be nonstereotypical.
I'm sure there are plenty of exceptions to this tendency, but it appears relevant to Barack's Obama's life story.