Are you coeliac or you just think that gluten is bad for you?
There are people who are "gluten sensitive" and my wife is one of them. More specifically, she is only sensitive to gluten in American products. She cannot eat anything with gluten here in the US without immediately having very painful stomach cramps and bloating. We spend about one month per year in Spain, where she is from, and she eats all the bread and gluten that she wants with absolutely no problems.
So, all I'm trying to say is that you shouldn't be quick to judge people who don't eat gluten and don't have celiac, unless they're just doing it because they heard it was bad.
In regard to the study, I didn't read all the info, but I'm not sure that 37 people is a convincing sample size. I've also heard other Europeans complain about exactly the same thing.