I have read that shorter baking time can have an effect on the gluten and increase people's sensitivity to it (can't find the study right now). Many bakers use methods to shorten baking time to yield larger output.
In Switzerland some bakers have started to go back to the old methods because of this.
This is my personal best bet. I think if we were to introduce a measure as simple as mechanical compressibility of bread (crust removed), and people with "gluten sensitivity" started eating very low compressibility bread, they'd be fine.
Also I think the FODMAP people are on to something important.
Naturally fermented breads that stay away from commercial yeasts (ie oldfashioned sourdough bread), work out for many people who otherwise struggle with normal commercial bread.
In Switzerland some bakers have started to go back to the old methods because of this.
Edit:
[1] http://www.motherjones.com/environment/2015/02/bread-gluten-...