I wonder where this idea originates. As an American, I genuinely don’t know of any restaurant that serves any of this (although I suppose you could special order “plain” things most anywhere in the world). I can’t begin to guess what people eat in the privacy of their own kitchens, but no one I know serves themselves these foods, either. I will say I’ve heard the same lore of “deep fried butter” existing at Midwestern fairs somewhere, but again, I’ve never encountered such a thing irl.