Hmm. I suppose people can choose someone of a particular race if they want to- its not illegal yet, is it?!
I think people get certain ideas of what is attractive to them as they grow up, perhaps often inspired by what they are familiar with, or other times what they feel are "Interesting" or "exotic" or just what makes someone stand out in the crowd. These ideas probably form part of the question of a racial sexually preference.
Although I don't exactly agree with the title, I would say in my personal experience, that I kinda think there is some truth in what has been said here- white girls are more likely to date a black guy than a white guy is to date a black girl. That would mean that white GUYS are sexually racist and perhaps white girls are not...
... or perhaps some of those girls believe that those black guys DO have bigger...!%&?!