he said he chose to be black.
I think most white-black mixed people (we have a name for them,
mulatos) identify themselves more with blacks, maybe because of dominant facial features, like hair or nose. It's curious, nevertheless. I was told that mixed people in South Africa used to be discriminated by both sides during Apartheid.
Despite being called black, I think being a mixed-raced is even more appealing in a sense, as he is in fact the result of a non-racist relationship, what is very positive. It's not just about accepting the other race, but that mixing is natural.
Of course Michael Jackson is another story. He is not black, nor white, he has a race of his own.

Regards,
Adelaide