Well, over nearly the last 4 years I think I've been turned down from a party maybe once a year due to the "JP onry" excuse. I've never cared who is where or what language others speak. Hell, I found some of my more enjoyable partys populated with non-english speaking players expecting me to only "Do My Job" and do my best to exceed their expectations.
As for the OP and his assumption of JP players being racist... let me 1st say, silly american. American egalitarianism is not universal. I do hope you're aware that americans are perceived worldwide as being rude, crude, mannerless, inconsiderate, ignorant, and too goddamned lazy to learn languages while having the arrogance to believe the world should learn english. Pick any one of these american flaws and you'll have a reason why non-NAs would choose to not play with NA's (sorry canadia, your beedy eyes and flapping heads get mixed in with us). While many non-NAs have accepted or at the very least tolerated NA's flaws, there will still be some that will just stick to their guns.
Better yet, if you get a JP only response again... have a beer and move on.