Caitlin Moran on why even drug addicts look down on people woth eating disorders:
"Overeating is the addiction of choice of carers, and that's why it's come to be regarded as the lowest-ranking of all the addictions. It's a way of fucking yourself up while still remaining fully functional, because you have to. Fat people aren't indulging in the 'luxury' of their addiction making them useless, chaotic, or a burden. Instead, they are slowly self-destructing in a way that doesn't inconvenience anyone."
Maybe this gets at the reason why everyone thinks over-eaters need to Just Stop Over-eating, while alcoholics etc. are "taken seriously" so to speak. Because in all other ways they appear (for want of a better word) "normal." Their lives aren't out of control, about to crash. You see this person who can run the whole family and hold down a job, so you don't feel the same sympathy as a drug addict who's life is breaking up.