Ignorance... that is usually the root cause
Muricans are poorly educated, half can't read past 6th grade level and most do not read unless forced to.
In this particular case they make fun of the French for not beating the Nazis in WWII because they probably saw it in a meme somewhere but their history knowledge does not go far back enough to realize how stupid they look when they do this "seriously"
you asked why that factoid was important... I tried to be funny by telling you that the girl one of these Paul idiots is dating is actually hot and OP brought it up because he is horny