Your sarcasm isn't really necessary. FYI, WW2 was more than 10 years ago.
But seriously, did you notice that the first real Vietnam games didn't start shipping until only a few years ago? Men of Valor was one of the first announced that I remember, though there were others that came about around the same time. That's a conflict that ended in 1975, with most major combat operations long since over by that time. And yet developers were extremely hesitant to make Vietnam games up until very recently.
It really has nothing to do with who they may upset; it has more to do with good taste and respect I think.
“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” - Mahatma Gandhi