1) As recently as the Russo-Japanese War, Japan was noted for their kind treatment of POWs. The "cultural misunderstanding" wasn't all that ancient a tradition.
2) Weird form of enlightenment there. So, it's very important to note that not *all* fascist Japanese were "genocidal, chauvinistic, racist murderers". One mustn't insult them. But "American nationalist, patriotic Nascar frat-boys" on the other hand--yeah, we don't want to come across as one of those!
This is a fascist country you're defending here. Not "fascist" as in "wants to cut the capital gains tax and not allow nudity on prime time TV" way the term is often used today--fascist as in jackboots and concentration camps and racial supremacist ideology. Presumably these are worse things than liking car races, being a loud drunken college student, or even over-enthusiasticly praising the US Marine Corps? If so, perhaps "cultural misunderstanding" could mitigate the latter behaviors as well?
PS You're confusing your class bias. "Frat boys" are generally of much higher social strata than "NASCAR" fans.