For your theorie I live in central Europe and don't know a single person with gluten issues. While the Americans in this thread make it seem like every 10th or so has it.
Something being widespread in a community doesn't mean that it's tolerated by everyone in that community. Milk is common in central Europe, but some people are intolerant to lactose. Tomatoes and red wine are also common, but some people can't have them due to histamine intolerance.
(I also have a central European colleague who has actual celiac disease. That said, I agree that the general gluten panic is way overblown.)
I'd wager half of them does not have diagnosed gluten intolerance.
There are many chemicals in bread one can be allergic or intolerant to. Gluten proteins are but one. Bad lactose intolerance and lactose sweetened breads may be responsible for some reported symptoms. Soy protein or bean protein used in fast mixes. Fructans are another.
