What are you talking about? Some hand-wavy paleo theory that isn't scalable?
I wouldn't go so far as to say they're not edible, but criticism of grains doesn't seem like outright crazy talk either.
I don't care what "some folks" beliefs are, I care about the ground truth.
It doesn't take a lot of equipment to deduce that billions of people eating grains consistently over the course of millenia means that people are in fact well equipped to eat grains.
"Bread and Other Edible Agents of Mental Disease
how cereal grains—the world’s most abundant food source—can affect human behavior and mental health. We present the implications for the psychological sciences of the findings that, in all of us, bread (1) makes the gut more permeable and can thus encourage the migration of food particles to sites where they are not expected, prompting the immune system to attack both these particles and brain-relevant substances that resemble them, and (2) releases opioid-like compounds, capable of causing mental derangement if they make it to the brain. A grain-free diet, although difficult to maintain (especially for those that need it the most), could improve the mental health of many and be a complete cure for others."
The Semmelweis effect is regarding rejecting new evidence -- and yet you provide no evidence, while dismissing mine.
Perhaps you should question your beliefs.
http://discovermagazine.com/1987/may/02-the-worst-mistake-in...
People live to be 100 and happy and productive on largely grain-based diets, not thanks to the grain, but thanks to the modern world it allows. Pre-grain, we didn't live so long.
On balance I think grains are a no-brainer. Maybe there is some extraordinarily minor benefit to the individual not to eat grains, but, obviously, in light of the past 10,000 years of history, grains are fine for you and will keep you both alive and happy.