And even if there's such a thing as gluten sensitivity (which it appears there is), we don't know if with proper treatment of the flour it won't go away. For instance soaking it with whey, or not refining it, might eradicate the symptoms. It's like people who are sensitive to milk, but who report their symptoms going away when they drink unpasteurized milk, that contains the lactase to digest the lactose.

Our ancestors might've known a thing or two about how to prepare these products for human consumption. Cos back then at least half of the world's population (i.e. women) did nothing but cook and discuss cooking among themselves and observe the results of their cooking on their growing children. Half the world were expert nutritionists!