I'm not sure the term "culture shock" is exactly correct, but I'll go with it since I don't have a better term. I experienced something like this just living in a somewhat different part of the country for college.
It's a rather sophisticated school (there's a negative sense for that term -- "sophist") and most folks there thought there were all that. They had never actually spent time west of the Hudson, couldn't tell the difference between Kansas and Kentucky and Arkansas, but they didn't think that really mattered.
I think that what it really was, I expected more out of these folks. Yeah, they were bright, but they were also, uh, poopy heads in their own way. I had some perspective that let me see their own flavor of stupidity and hypocrisy. Of course, they couldn't see that.
Eventually I quit beating myself up. Screw 'em. I stop caring what they thought, didn't want to worry about letting them know there are other places in the US besides NYC, Boston, and LA, and just focused on my studies and being done with them.
I think you had your expectations too high, Danny. The Japanese are probably, on average no more or no less of Richard Noggins than Americans. It's just that you can see it. Don't take it personally. Don't try to change them -- you can't. I'd suggest either thinking screw 'em, or else pretend to be an anthropologist and be amused by them.