A lot of people might not think of themselves as racists in the extreme sense of the word. But all people are, in some way, biased when it comes to race. You can't help it.
I'll prove it. What's your favorite color?
Aha! You have one! (Most people do.) So you are biased based on color.
Now, let's say you are thinking about dating someone. If you could date and make-out with anyone, would you have a preference as to what they look like? You do? Then you are operating on preconceived notions of who you want to sleep with. Is there a race that you would exclude? Come on, you can't be politically correct about what turns you on- either it does or it doesn't. Why play games? Since you would probably exclude someone out of the romantic or gratuitous sex category, based on racial preferences, does that make you a racist?