You're welcome to have your own definition of chunky, and I'll have mine.
Attitudes like these are why we have so many problems with eating disorders in this country.
I hope you're just arguing for the sake of arguing, and you haven't actually bought into the media's over-sensationalism of eating disorders. Obesity is the big killer in this country, not anorexia/bulimia. You should be concerned about the messages being sent to people who eat too much, not people who eat too little.
How about this? People are either fat or they are skinny. You don't see idealized weight being promoted as healthy. All you see is too thin and too fat. The media is quick to jump on either but slow to acknowledge when someone is actually the weight they should be.
Brittany Murphy was slightly overweight in Clueless. I wouldn't even have called her "chunky" much less fat but others did and then she took the extreme opposite side and became too thin.
Regardless of whether weight gain or loss is a genetic, social, learned or other issue, it's still an issue and people who go too far either way are going to suffer for it.