In one of the best examples of science working, a researcher who provided key evidence of (non-celiac disease) gluten sensitivity recently published follow-up papers that show the opposite.
This linked article explains it a bit better IMHO.
Coincidentally, some of the largest dietary sources of FODMAPs -- specifically bread products -- are removed when adopting a gluten-free diet, which could explain why the millions of people worldwide who swear by gluten-free diets feel better after going gluten-free.
So perhaps what people are searching for are low FODMAP diets. Since a number of other possible irritants (lactose, benzoates, propionate, sulfites, and nitrites) were excluded from the diets, I wonder if part of the NCGS has to do with combinations of irritants, or even interactions between them. Someone might have some ready-mix pancakes, get milk, benzoate, and FODMAPs in one serving, and wrongly attribute their ill-effects to the gluten.