You raise a very good point. They will involuntarily hospitalize anorexics/bulimics who are at the point where they are close to starving to death. But they don't do anything for the morbidly obese. They don't even hospitalize overweight people whose weight has nothing to do with over-eating, but because of something biological that's causing the weight gain. (And I can attest that it's possible to have severe, even rapid weight gain, and not be over-eating as it's been happening to me. )

It may be because of the stigma attached to being very overweight. Being thin is viewed as a sign of self-control, beauty, mental stability, desirability, self-respect, etc. Obesity, no matter what the cause, is viewed as a sign of gluttony, greed, laziness, lack of self-respect, etc.

I think maybe because of this, anorexics/bulimics are looked-upon favorably and with sympathy, while extremely overweight people are looked upon with disgust. Anorexia is viewed as a disease, while obese people are viewed as just having bad habits that they are too weak to change.

--Ceara1010