Why do people look down on parents who want to feed their children healthy foods?

I was at a my grandmas house the other day and my aunts were talking about a family friend of theirs who is pregnant with her third baby. My family was saying how she's crazy and her kids will grow to resent her because she doesn't give them a lot of junk food. Why is it acceptable to judge someone when they are feeding their children healthy foods, but it would be rude to question why they feed their children cheeseburgers? They have said this stuff to her face as well.