WWII in Germany...

[Alardem]

Following the second world war, Germans are conditioned to feel extremely guilty about their Nazi past - at least, the west Germans were. The east Germans were busy being occupied by the similarly totalitarian communists. You'll find neo-Nazis anywhere, even in Russia, but they're not at all mainstream.

So yeah, Germans come off as a bit over-reactive to simulated violence. Green blood, no swatzikas for entertainment purposes. I've heard of some games which have been made unplayable in Germany because they involved Nazi content: they made I Have No Mouth And I Must Scream unwinnable by removing the Nazi doctor protagonist.

Japan is a different story. While they don't necessarily deny their grandparents' crimes in World War 2, coverage of it is underplayed. Consequently, I don't think they're any more squeamish about violence than Americans.