So I had it pointed out to me that in the most recent Harry Potter movie Young, White, British Harry shares a kiss with a girl of obviously Asian descent (that would be Cho Chang of Hufflepuff, yes I know this stuff).
Yes, cool, I didn't think that it was a big deal, really, if I were fifteen, I'm sure I'd have thought she was cute (me being about twice that age, I'd go for Tonks personally, I've always been a sucker for the funky hair) but I didn't see it as any big deal.
But after thinking about it, I guess there is a certain percentage of the population who find a Euro-Asian pairing to be kind of exotic, and there are some who will see it as "if it's OK for Harry, it's OK for me."
Great. I also realize that, although the population of minorities at Hogwarts is small, it's probably relatively representative of the population at large. I seem to recall Ron going out with a girl with the last name Patel (somebody correct me if I'm wrong, it's been a while) and various other ethnic mixings, all without the bat of an eyelash.
Of course, when you deal with giants, centaurs and the like, minor differences in skin tone probably seem pretty insubstantial, and the cultural difference between the wizarding world and the normal one are pretty broad.
Actually, the obvious treatment of racism comes in there, more than any regional difference, with the whole concept of "Pureblood" wizards, again, though, the bad guys are the ones that care about that sort of thing (and does anybody else see something Hitler-ish about this Voldemort guy? Really.)
So, while in the real world, people blow each other up over the way they worship what is essentially the same god (and no, it's not just one particular group, think about that for a minute) in the most popular English-Language fiction on Earth, teenagers are telling the racist grown ups to stuff it, friends are friends.
Impressive. Although I still think getting people to read anything is the biggest accomplishment Rowling's had.
As for myself, I'm not sure that I never remarked on Harry's relationship because I'm so accepting of such things, or because I'm so unobservant that I didn't notice.