Are these people raw paleo? I could eat plenty of raw garlic with no problems whatsoever while I was eating unrestricted cooked. Now on raw paleo however, it's same experience as yours.. I even get headaches, not only stomach pain.
Yes they are eaters of cooked food.
Ayurveda explains that the garlic is a digestive, so it helps to motivate the digestion in people who have low digestive powers generally for whatever reason. Many things do this and onions is one. Usually associated (but definitely not necessarily) with people who have weight issues.
If someone is like this their intestinal tract is likely to be coated with a liberal dose of undigested food and is a perfect candidate for a laxative treatment.
My ex was like that. She could sit down and eat a raw onion. Straight uncooked.
When I went to a Vaidya with the family, he suggested to her to try a dose of 1 - 2 tsp of castor oil. The result was somewhere between hilarious and mind boggling.
When it started working, first she sat on the toilet and actually completely filled up the bowl twice, to the point where it had to be flushed. Then when she finally finished, she got up and announced it was meal time. Since she was always not the hungry type, I dawdled a bit getting ready, so then she announced it again shortly after. A short time later she announced she was going out the door to a restaurant (We were at a hotel) and left. She had experienced hunger for the first time since I had known her. It was amazing.
Her mother had died of bowel cancer. I have no doubt that if her mother had've taken castor, she would still be alive today. Funny thing about preventative medicine is that you never know that it prevented anything, because you fail to get sick.
Ultimately I repeat once again ad nauseum, that I believe eating raw would have prevented her problem, negating the need for the castor.
I on the other hand can practically digest nails. Milk can be a bit of a problem for some people to digest, but for me. I almost need it to slow down my digestion. It may be somehow associated with my eating so fast, not sure whether eating too fast causes my digestion to speed up or whether my digestive strength allows fast eating so I do. Fascinating question.....
However pasteurized is a no go for me. The only way I can drink pasteurized milk is to bring it to a boil, take it off the burner, till the foam settles then, put it on again till it foams, then take it off, add turmeric and ginger ( an Ayur. recipe to increase digestibility) and then drink it.