How come people see music as black or white people music?

People think I wouldn't like rock because I'm middle eastern. It really pisses me off. I guess they think only a certain type of people can enjoy a certain type of music. I actually recently went into a New York music store and asked where the rolling stones were, and the girl stared at me like I was crazy. Ugh. Sorry for ranting. It's just that the whole world is already so prejudice, and on top of that I have to be a certain ethnicity to like rock and country. I hate it. This wasn't really on topic though lol XD