You are still lumping fat people together and trying to explain the obesity. If we set aside the excuses and explanations provided by the obese population you still have a problem trying to explain all the obesity. When scientists study these people they discover that things aren't as simple as they imagined. There are mechanisms that fat people have that make it easy for them to gain weight and almost impossible for them to lose it permanently. The success rate for fat people dieting is something less than 5%. In other words, 95% of people who diet regain that weight or more after 2 years. That is a fact and a very challenge to all the musclemen who think they know it all. That program The Biggest Loser is a pathetic view of obesity and how to reverse it. I wouldn't give those exercises to my members who are trying to lose fat. It is amazing the ignorance of the people who produced that show. Their instructors are knuckleheads, too, and give the fat people really stupid things to do. I guess it makes good TV. Well, I don't watch that show because of all the foolishness involved.
As more research is done on fat populations things are discovered which takes some of the blame away from them. They are motivated not to be really fat but get that way, anyway, despite their best efforts. If you worked in a gym and had these members as clients you would soon change your mind about protocols and ideas that will reverse the obesity.
I agree some of the obese do have a genuine medical condition that doesn't allow them to shed the fat easily. But there are also a lot of obese people who are fat simply because they can't restrain themselves when it comes to food. This latter group of people then bunch themselves with the ones who have the real problem and make it appear like they too have a condition that is beyond their control.
The success rate among them when it comes to weight loss is so low because of multiple factors, including, but not restricted to,
1) Their having little will power and commitment to lose the fat, which takes a long time to accomplish and entails giving up on their addiction i.e. food
2) Their giving up too early due to the above reason, as well as the fact that they don't see any noticeable difference in their weight loss after sticking with the new, "difficult" diet for a while, which discourages them to give up and depresses them enough to revert to their old eating habits
3) They get desensitized to their condition and accept it, which is easily accomplished by teaming up with other fatties, who become a support group and a refuge where they can indulge in their habits without any guilt.
The number of obese people has risen sharply in the last couple of decades, with the increasing availability of fast food and the range of snacks plus the different venues you can get them from. That is no co-incidence or even a correlation - it's a direct causation. They eat more, more often and get fatter. Again, not all of them, but definitely most of them. The number of fatties with genuine medical problems can't have just risen dramatically out of the blue for no reason.