Body image issues aside, I just could not imagine going through life with so little upper and lower body strength. Just seems so impractical and inconvenient to choose to be this way.
Many that are "this way" aren't by choice. And it's still less handicapping and unhealthy than being obese. I'm not excusing their agenda, just pointing out what you've said is dumb as fuck.
You're just repeating someone else's sypthities regarding different people with body image issues. If this were a child who got anorexia through exposure to pop culture, then their responsibility to their condition is lessen, but these are fashion models. They're the ones perpetuating the toxic cycle. They're grown adults who have the resources to remove themselves from the situation and seek help. If they're not the ones choosing to be this way, then who is?