It's so common people don't even see it. But it's the same thing as Mexican food. The perception is it is spicy and will give you diarrhea.
I firmly believe this is because American people in general don't understand what spices are. Spiced does not mean spicy hot. Spiced is flavourful and they just can't have that. I have dined with Americans that truly believe black pepper is too spicy. We had a Starbucks chai which is absolutely terrible, and they've said "it's too spicy"... What? Their brains equate flavour to spicy heat to bad.
It's stupidly infuriating.