It's not bungled, it was an intentional, lightweight slur. Whoever downvoted you is ignorant. What were some slurs the Germans used for Americans in WW2?
Yeah, long refused to use the term as it seems like a slur. Most people consider military jargon used for enemy combatants to be offensive in a civilian context.
Emphasis on "lightweight". My impression is that Americans in ww2 used up all their slurs and disrespect on the Japanese and acted towards Germans almost as if they ("we", I'm German) were civilised people, politely agreeing to disagree. Even American caricatures of Hitler himself seem strangely benign compared to those about ww1's Kaiser.