OK, I must ask for the patience of other posters, since I will have to explain this cartoon.
This cartoon suggests no such thing, and neither do I.
USA is of course not a Nazi society, but it clearly has fascistoid traits which seems to grow stronger under its current administration.
Relevant here is e.g religious fundamentalism, chauvinism, croonyism and cooperation with big business, imperialism, and the belief that international conflicts should be used with the help of military actions.I see all those abundant in US politics..
There is absolutely no reference to genocide, race supremacy or totalitarianism in that cartoon, but rather a gentle hint that certain actions and arguments defending those are to be condemned.
I might also add that it is a heavy responsibility upon every decent American not to develop the country into a direction which would actually make such a comparison relevant, even it if is a far way to go yet.Because the chosen direction seems to be the wrong one...