New Mexican Chiles and Guajillo chiles are both cultivars of the same chile, you’re right there. But broccoli, mustard greens, kale, brussel sprouts, and cauliflower are all cultivars of the same plant too, which I think illustrates just how different and distinguished cultivars can be. New Mexican chiles were cultivated in modern day New Mexico, not Mexico. They’re a cornerstone of New Mexican cuisine and not Mexican cuisine.

Find me a few traditional places in Mexico serving tacos like they have in Torchy’s or Velvet taco and I’ll gladly concede every taco is Mexican food. Sure, the tortilla is Central American in origin, but sticking a hickory smoked jalapeño and cheddar sausage in it isn’t. Cajun food isn’t French just because it’s heavily influenced by French cuisine. Italians will tell you gratuitous foreign pizzas are not Italian simply because they drew inspiration from Italian food. What makes Mexico so special that it can claim all derivative cultures as it’s own while denying that it itself is a derivative culture?

Anyways, I’m done feeding the troll. I think I’ve conclusively proven the distinction, not that it needed to be done, since it’s fairly obvious for anyone who’s experienced the cultures and foods.