By "experts" you mean doctors?
Yeah, I'm guessing there wasn't too much research on gluten intolerance a few centuries ago. Cool that we have it now and people and people with these issues can feel better, or not?
My suspicion is that there is corruption going on with doctors and the gluten test they perform. With most allergy or sensitivity food testings you are told to avoid the food/spice for a period of time (1 to 2 months) and if you feel better keep avoiding. At least that was my experience.
Wheat is treated differently. Doctors say to determine if a person has a wheat gluten problem, an upper GI exam is necessary. The test takes about 30 minutes and costs around $3000 to $10,000. During the test a small sample from your intestine is removed. From that intestinal sample they say they are able to determine if a person has a problem with wheat gluten or not.
A problem is that the upper GI test is not definitive. What the doctors are looking for might not be found on the sample. As doctors say the intestine can be spotty. Some parts of the intestine might be damaged, and other parts not damaged. Additionally other foods, or even a common cold might cause the damage they are looking for.
All my gluten/wheat tests came back negative. I had 4 tests done in my youth. Today, learning what I suspect is going on, if another doctor suggested I have an upper GI wheat test done I'd tell him I'm not interested. Even though all my wheat gluten tests came back negative, I have one diagnosis from a doctor of having a problem with wheat gluten. That is due to me feeling better after i avoided wheat.
There is little doubt that wheat and other grains are a problem for some people. Doctors great attention to wheat though might be due to the special wheat test they can perform and be paid well for. The test makes them good money and does not take long to perform. If insurance companies and government health agencies stopped paying for the upper GI wheat gluten test I suspect that most "essential" upper GI scope wheat testings would stop. Wheat testing then would be similar to other types of foods, avoid for a month or two and see if you feel better or not.