Perhaps the fact that the food could literally be poison for the person eating it? And if this person has no communication skills... At least when you're 3 and

Perhaps the fact that the food could literally be poison for the person eating it? And if this person has no communication skills... At least when you're 3 and talking you can be more clear about what's going on with your body if there's a problem. "Why give them any food at all" is a very glib reply to them. I'll let you figure out why people might avoid certain foods and not others, and why people feed small children