Didn't say that. WWII was a case where legality and morality overlap more conveniently which is why it is a favored topic. Still debatable in many aspects e.g. Nagasaki, firebombing cities, not bombing the concentration camps, etc., but in comparison to say Vietnam, you see the point. You don't see too many films these days celebrating the nobility of unquestioningly doing one's duty to support the righteous fight in Vietnam.