OP, not very carefully worded OP.
But surely, I cannot be the only person who sees where you are coming from?
I see some huge people, and I wonder how they got to be that way. I am curious, in a way I wonder if it could happen to me. I don't know the answer.
I do know however that these days a lot of people do not seem to take (or accept) responsibility for their own lives, be it debt, weight, health. Too many people on TV and in magazines saying things like: "When I was 11 someone called me fat. I have had eating issues ever since and am now 16 stone", or similar. Or people who blame their genetics, their parents, their unhappy lives. As you can see from the responses on this thread, it is a highly emotive issue, and you'll get lots of hate mail.
When really, it's a valid question. You don't suddenly wake up size 24 one morning, you must have gradually had to buy bigger size clothes right?
A friend of mine who has studied Obesitas says that it is inevitable that we all get bigger, with the easy availability of (junk)food everywhere. Most humans when having to choose between short term reward (tasty treat) or long term reward (being slim and healthy) choose the short term reward because humans are wired that way. Having abundant cheap food available is a fairly recent phenomenon for mankind (and not everywhere in the world!).
The really interesting question is, IMHO, "Why are there still so many people who are NOT too big?!"
A friend of mine who is "effortlessly slim" says her being a size 10 is a decision she makes every day, involving saying "NO thanks" to lots of biscuits, cake, and fast food.
I think the only thing that will stop widespread obesitas is for food to become scarce.