Why do white people stick to their own kind?

I'm of Indian origin, but I'm born in the UK. Most people think that I'm either Spanish or something of that sort, plus I don't really relate to Indian people, but that's not the point. My whole life, I've found myself drawn to black people or Spanish people, as I find that I have a lot in common with them. Now that I go to uni, white people are everywhere, but when you sit next to them in lectures and in cl, they won't even try to start a conversation with you, unless you're white. I think that this is blatant racism. Who says that racism doesn't exist? It bloody well still does, and this pi sses me right off. Today in cl, I had to join another table which had a white boy and girl, and an asian girl, and through out the whole lesson, the white boy and the white girl were constantly talking to each other, whilst me and the asian girl just sat there staring into space. I just think that white people don't have any manners whatsoever. They also stare a lot, on the tubes and in cafes, and they say that foreigners don't have any manners - hypocrites. Discuss.