There is no “black people like this music” and “white people like this music” that is inherent in human beings. That’s the important distinction to make here. However, trying to disregard the obvious differences in musical tastes within a society is silly – because they do exist and they exist for reasons. That is not to say ”all black people like this kind of music” and ”all white people like this kind of music”, but these differences in musical tastes exist for many varying reasons. The American society, as a whole, is, well… Not a whole. There are micro-societies within it, that take shape based on many things. Age, race, gender – just to name a few. All of these micro-societies function the same way the overall American society would. They have rules and ideals, ways to behave and not behave. When you look at it that way, it makes sense that there might be a difference in musical tastes among many black and white people.
But again, this difference is not inherent. If you took a black and white baby, as someone else suggested, and put them in a room together – they would both inherently gravitate toward music in general. Rap (for instance) was music that stemmed, originally, from struggle. How hard life was. Which is to this day, typically, something that many black people understand better than white people in this country – because white people still hold the most power. They enjoyed it because it was a part of their culture, something that they could identify with. Now if we look at some rock in a similar light – maybe so many white people seem to enjoy it because it’s expressive and angry – something that, typically, can not be expressed in “polite” company in white culture. Essentially, both rap and rock catered to the individual cultures and gave people an outlet for shared feelings.
As time goes on and people begin to mesh more and more, you will see these obvious differences (based on race) in taste dissolve. People will no longer be restricted within their own cultures – no longer subjected to the limitations placed on them by society in general. Everyone has different life experiences, and those experiences shape who we are/become. Right now, because we live in a society where the things we experience are unfortunately based on “race”, our experiences will typically differ.
Now… A reason that white people might be seen to express more interest in “black” music (in overly-simplified terms for the sake of length) is because, as stated above, white people still have more power. We aren’t as limited in what is and isn’t “okay” to be interested in – because white people, for the most part, still make the “rules”. Also, with a lot of (especially) younger generations… This divide between the “races” is disappearing. They haven’t grown up, as much, with such a clear division between black and white people, so they are completely comfortable stepping outside of what was once “normal” for their race. This may seem especially weird to some black people, who might think “what the hell does a white person know about this kind of life?” – not because that black person is racist, but simply because that black person is more aware of the fact that that white kid is generally provided with more opportunity in this society.
I’m being way too much of an anthropologist right now. To end: It is strictly societal – not inherently based on “race” (no such thing, but that’s another topic for another time). If the roles were reversed exactly as they are now, something similar would have happened.