I will start by saying that I am a white male. I have attended three universities, all in the Great Plains where a majority of students are white. I will also say that I am very excited to attend a law school in a city with more diversity.
If someone chooses to date exclusively within their own race, who cares? I am not running your life, and couldn't care less about your dating habits.
Now here is my anecdotal two cents (completely unscientific), and I am speaking in generalized terms. I prefer dark hair and dark eyes, I really don't know why, I just find those traits very attractive physically. I find many hispanic and black women attractive, but I also find them very intimidating to approach. This is partly due to my general insecurity and shyness with women. I also believe that approaching women of a different race is intimidating because I don't know if they share my views about interacial dating. Up to this point I have only dated one black woman and no hispanic women

. We had a great time, but it just didn't work out. I think you can learn a lot about life from someone who is completely different from yourself.
From my experiences, I find that many black people seem to be more racist than the white people I know. In the predominantly white schools I have attended, many black men (many of which are athletes) date white women and it seems that both view each other as a trophy. From the black men that I have talked to, it seems that a lot of them want to "bang" white girls, but would only seriously date or marry a black girl. I think a lot of white girls want to find out just how "big" a black guy is. Some of course are serious relationships, but a lot of them just seem to be about sex.
I do think that black girl/white guy relationships are becoming more common. I believe that one reason may be the belief (generally speaking) that white men treat women better than black men, and black women who have had a few bad experiences with black men are willing to give white men a try. I also believe that white men are becoming more open to dating outside of their own race (doesn't everyone like a nice butt?).
Anyway, date who you want, but I do believe that limiting your relationships (friendship or dating) to people just like yourself truly limits your life experiences. I realize that I have spoken in generalized terms in my post, but in reality every individual is different and cannot be placed neatly into a category (which probably makes my post stupid and irrelevant), so please keep the hate to a minimum.