Noone says "I'm gonna be a fat guy".
Nobody says "I'm going to eat all I want and not excersize and gain 300lbs"
Noone says that. It's not a "choice", a choice occurs when you look at the options and you choose something.
If you become fat, it's because something has gone wrong, either in your physiology or your psychology. It's a symptom. The attitude that these people can just "Stop eating so goddamn much and exercise" certainly doesn't help. If they overeat, it's a compulsion, and probably one they feel bad enough about without people making them feel worse (which of course will have the opposite effect). Again, noone says "I'm going to eat this whole cake". A fat person with an eating problem will see the cake, and unless there are clearly evident reasons at that moment NOT to eat the whole thing, they'll eat the whole thing. It's not a choice. It's a compulsion. Everyone has a compulsion to eat. Every single human being on this planet that isn't dead, has a compulsion to eat. People with eating disorders however, don't have the same triggers, both physiological or psychological that tell them when to start or stop eating. That's what the disorder is.
As for exercise, I don't think any of you understand what getting a morbidly obese person to exercise is really like. They can't just "go for a run." Even walking in some extreme instances can cause severe injuries. For even less severe cases, they don't generally have the stamina to go very far, or work very hard. Their respiratory and circulatory systems are so strained just existing that they can't put in the work to make them stronger.
So take an eating disorder, one that is not scene as a problem, as opposed to anorexia or bulimia, which are seen are horrible horrible things and is often ridiculed, let that fester for a few years doing the activity that isn't any more sedentary then their peers, and suddenly they're fat. Now that they're fat, they can't even do the non-sedentary stuff they did before as easily, so they do less and less of it, until finally they do nothing. But because they have an eating disorder and human beings CANNOT JUST STOP EATING, they get fatter and fatter, and less able to do things and more disgusting. Friends start going away, eventually, they're alone, and fat, and ugly, and have no emotional support. They just look at themselves in the mirror (If they can even stand to do that), and say 'Well, fuck it, I guess I'm just a really really fat guy now'
All that, and really I never covered "genetically predisposition", because I think it's largely a crock. Fat people have fat kids because fat people don't know how to eat properly, and they feed their kids in the same way that they feed themselves, hence, their kids get fat and don't learn how to properly feed themselves. There are of course physiological problems, such as thyroid problems that can screw with a person's weight, but those are usually treatable with drugs, and if that's all it really is, then it's really nothing. I think when we talk about fat people, we're talking about people that are just fat because that's what their outlook on life and drilled in habits have made them.
Are they physically disabled? Yes technically, but I'd go so far as to say people who are morbidly obese are mentally disabled as well. No one with a right mind would let themselves get to that point. It's not like being classified as disabled makes their lives really all that great. If they can't physically work anyway, then really, all you're doing is elevating them to the point where they can exist. If you don't think they should exist, then really, fuck you. They're human fucking beings. If you think that somehow being disabled makes them feel important or makes their lives so great, fuck you again, you have no idea what you're talking about. No one is proud to be on disability. Noone WANTS to be disabled. Noone's like Hell, I think I'll just be disabled, and that's what my life will be like. They may want to get on disability, but that's just so that they don't have the added stress of being possibly homeless on top of being fat and disgusting. They would much rather a life where they didn't have to go on disability.
I really don't think I have much else to say about this. I wasn't even going to post anything, and ended up posting a huge rant, but I really think you people have no clue what you're talking about, for the most part. If you don't know what you're talking about, chances are you probably shouldn't talk, or else you just make yourself look stupid.