I think spicy food is eaten in Spain, in India and in Thailand, because the spice acts as a disinfectant, which removes all kinds of germs (and therefore diseases) from your body, which is especially important in hot and humid climates, because bacteria spread like crazy there?
That’s a good point.
Also, spices can hide the fact that the food’s gone slightly off due to improper preservation (at least until it comes out one end or the other in a ballistic fashion, but then it’s possibly too late to pass the blame), so there might have been a bit of that, too.
Still, it’s funny how we love eating stuff that’d kill or seriously inconvenience most everything else.
We are weird creatures indeed.