why do we have so much discrimination?

Why do we have so much discrimination in the world? I think it's stupid and disturbing. Like all this anti semitism against other races. I was watching this movie called American History X and it was so unsettling to watch. It was about this white aryan race called the "skin heads" and they basically hated everyone who was not of white skin. Isn't that horrible. I think its disgusting. Why? As I watched derrek the leader of the cult shoot 3 black men and make one of them put their teeth up against the curb so he can step on the back his head and snap his jaws and neck, I thought that I was going to puke . It was disgusting. I do not like how people do that. Every body is human and I could see if we had demons or aliens then we could discriminate them because they are not human. But people who are black, jewish, latin or anything don't deserve to get treated the way they do just because they are not white. Are white people better or something? no . Is it because white people have the image of being more rich? yes. But don't forget there are alot more people who are more rich than any white person alive and they are not white. So there really is no diffference.