Great post, granny. I have been low carbing for a long time - I have lost 92 pounds- and have learned that it works for me. My blood work, body, and energy level has never been higher. As I get close to goal I am gravitating toward a paleo diet. That suits me even better.
A friend of mine does WW and it works great for her. She is happy, has figured out how to maintain, and I wouldn't think of trashing her WOE because it works for her.
I also agree on the food intolerances. Through eating an ultra clean, no processed food, no dairy, no grain diet for a few weeks I was able to really clean my body out. When I started to add foods back in, I was surprised at how apparent the allergies/intolerances were. In the course of this testing I have found that in addition to most dairy and all grains, I have issues with eggplant, peanuts, pumpkin, and a number of other foods.
I would never push Atkins on someone else or tell them that their chosen WOE is horrible. I expect the same courtesy.