Why? Well, for starters, because it's not made with corn.
[cue cricket chirps for awkwardly long pause]
Aside from gluten and dairy, I also have a sensitivity to corn. I discovered it in the year or so after removing gluten from my diet, when my diet took a marked turns towards increased indulgence in corn tortilla chips with guacamole and salsa, popcorn, and delicious breakfast tacos, enchiladas, and tamales. I am in Texas, after all. However, after eating these items, more and more I was being seized by seemingly inexplicable abdominal cramps along with hives all over my body. One would think that after discovering a major food allergy that I would be better able to put two and two together. But I honestly think that at the time, after suffering from food for so long and finding actual relief that didn't come in the form of a pill, I wanted gluten-free to be "the answer."