In fact, given the American love for sarcasm and hyperbole, and lack of an actual historical Nazi party of any note, it seems to me less likely for one to interpret the label literally.
A clear example of this is if you take fringe idiot politicians who say populist stuff and have zero workable policies. In the UK, they're a fringe political group like UKIP. In the US, one was just voted president. Here was a guy with a famous history of scamming (indeed, he was the poster child for it), making obvious and contradictory promises he couldn't keep even if he wanted to, and with no detail as to how. His whole platform was telling people the superficial stuff they wanted to hear. How did he do? Almost half of the voters individually voted for him, in a strong voter turnout. The only thing missing from his obvious scam was twirling a waxed moustache, and still nearly half of American voters went out voluntarily and voted for him.
"c. colloq. Used to indicate that some (frequently conventional) metaphorical or hyperbolical expression is to be taken in the strongest admissible sense: ‘virtually, as good as’; (also) ‘completely, utterly, absolutely’.
Now one of the most common uses, although often considered irregular in standard English since it reverses the original sense of literally (‘not figuratively or metaphorically’)."
(http://www.oed.com/view/Entry/109061)
The earliest example given, incidentally, is from way back in 1769.
It's like that in America, what things are called is more important than what they are. Obviously there are plenty of Americans perfectly capable of understanding context, but they don't seem to be in control of the political narrative.