I always thought the main reason to stay away from peanuts was because of aflatoxins. Here's one opinion from Dr. Weil:

http://www.drweil.com/drw/u/QA/QA115491/

The other reason is because it has arachidonic acid, found in saturated fats, which causes inflammation. Arachidonic acid is found in meats, particularly poultry.

I think the problem is when we separate components in food rather than looking at the food as a whole and how that acts in the body. I can't say that I'm crazy about the paleo diet or any diets like it, such as SCD. I've been observing what I eat, and I find that an omnivorous diet is best. If I don't eat any grains, I don't feel well. If I eat too many grains, I don't feel well. Moderation, diversity, and whole, unprocessed foods seem the best for a balanced diet. To me, foods that aren't tolerated are probably due to somekind of bodily illness or imbalance, or perhaps a result of genetically modified foods.

Claire