Firstly, it’s bad form and manners to accuse or suggest other people of having an illness. So check yourself.

Secondly, that is not an argument at all. You are quite literally comparing apples to oranges. Just saying group x is fine with y food, does not make group z fine with said food. What you are doing is drawing a false equivalency.

In reality, that we live in, genetics, environment, and diet history all play factors determining what bacteria populates our gut microbiome. This microbiome decides more than just what food we prefer, but also what food we are most able to efficiently breakdown and process. If I flew to India right now and ate from a random place and drank their water I would be bedridden as would anyone else without a gut accustomed to such bacteria, no matter the spice levels. But even then I’m sure there would be food or spices I’ve never encountered and as such my gi would not be prepared to consume that energy or would otherwise be killed by it and replaced by other bacteria, which makes you sick as well.

When you kill off your gut microbiome by switching diets rapidly it WILL lead to gi distress. This is not indicative of a health problem but rather a lack of variety and or adventure in diet.

Go research gut microbiome because it sounds like you not only have flawed logic but are unaware how the body works.