Another example; I live in a city of which 50% is not native Dutch and I have always been to schools where all cultures are accepted. Yet all my friends are Dutch. I don't think I'm racist, yet why don't I have multicultural social contacts? I don't know. Makes you wonder if racism is built in, right?
I lived in a city which was massively multicultural, too. I had friends from all ends of the world, all showing off their ethnicity. We acknowledged each other's race, but we didn't discriminate each other based on race - or at least, I certainly didn't. Some races still tended to stick together when it came to more private situations (ie best friends), I noticed that. But sometimes that is down to culture, personality, which classroom you were in (our school created classes based on IQ test results, and certain racial stereotypes were not done any favours by this, sadly)... it's not always a race thing.
I think saying racism exists to small degrees in almost everyone (if not
everyone) is still potentially accurate, but with some people it's to such a minimal degree that I don't think it's worth calling them racist, so much as pointing out that certain things they do could be racist. Saying we're all racist on some level is like saying we're all evil on some level, when really there are a lot of very good people out there who happen to have a couple of bad things that they might do or have done. It doesn't make them evil by definition.