Yeah, I tried to explain something similar to a family member re: the difference between margarine vs butter or animal fat. I took this approach:
"What's in butter?"
"Right. What's in animal fat?"
"It's just animal fat...."
"Now read the ingredients for margarine. Do you know what half of those things are or what they do?"
Ah well. I take what small victories I win but otherwise let them do their own thing. As long as it doesn't affect me, they can do as they please.
PS: Check facebook, sir.