White guys who don't have a problem with that either have a beautiful girl themselves (so they don't care) or they are metro man with no balls.
Or they're busy with German girls in the dunes.
In natural history it used to be normal for single guys to get angry when seeing a girl of their own tribe dating a guy from another tribe.
In the earliest days of humanity, humans used to be nomads and hunter-gatherers. They travelled the whole globe, traded goods with eachother and never actually settled down in one place. The smaller their numbers got, the less chance they had of surviving, so they actually had to team up whenever they encountered another group, and they actually had to cooperate to survive. There's a lot of evidence which suggests that the earliest humans didn't wage war with eachother, apart from a few isolated cases which probably had to do something with rivalry, in most cases probably to settle disputes about who had the leadership over a group. Oh, and exchanging partners from tribe to tribe was actually quite normal, because it ensured healthy offspring and prevented inbreeding. (We're not necessarily talking about race here.)
Now get back to find your natural feelings, you brainwashed boy!
I'm willing to bet he experiences more natural feelings than you do on a monthly basis, but ofcourse you're too busy to whine about black guys to notice that, instead of picking up your balls and actually approach a girl.