IMHO racial diversity is not a preventive of racism.
Rotterdam is the most racial diverse city in the Netherlands (just over 50% non-native people) and there is still racism here. Sure, it's a minority that is racist, but they are here...

when im back at home ill try and find the quote in the mag

I suppose you're right M but I've never found the city to be outwardly racist. Maybe because I went to school with such a diverse group I don't notice it. Until I got to college I didn't know there was such a thing as an anti-semite. My guess is there's a fair amount of racism between the Hispanic and Polish communities here because they both dominate the trades.