[tomp]

> many of those allergies are just diets with parlance that cooks easily understand

Absolutely. My dad has a strong aversion to garlic - it's not an alergy, he just can't stand even the faintest taste of it in food. After years of telling the waiters "absolutely no garlic" and the waiters bringing food with garlic and him complaining and the waiters answering "the cook said it's so little you shouldn't be able to taste it" nowadays he just says "I'm alergic to garlic" and he has problems much more rarely.