But food-based apartheid is created by all sorts of things. Food allergies, intolerances, alcoholism, and just plain taste. It is part of a good host's job to find out any of these things about dinner guests, and to plan a menu accordingly. Broccoli haters can usually detect the stuff without having their attention drawn to it, but the polite host will inform someone with nut allergies about the dish made with peanut oil. Those of us with unusual intolerances (oatmeal? chocolate? onions?) are accustomed to just avoiding the intolerant dish without making a fuss.