There are two sides to american eating habits.. the ones who think the Wendy's Ghost Pepper fries were too spicy, and the ones who are actively out there inventing a whole new level of spice to torture their taste buds with.

Sadly, the first side is WAAAAAYYYY larger than the second and any level of spice stronger than black pepper will instantaneously send them both to the bathroom and the emergency room for even daring to try something with some flavor on it. And it doesn't help that as far as most people (around here anyways) consider indian food chicken tika marsala and samosas.. and that's the entirety of the menu.

The only other thing I can think of that might cause it is the intention for each bite of bland food (like rice) to have a surplus of flavorings on it, which works for most non spiced foods but may wreak some havoc on people who don't balance out their spice intake with the rest of the meal. There's probably something to be said for overall quality causing some problems as well.

I can't be sure, but from the people I've interacted with, these are reasons I can think of which may explain how things got to where they are.