I agree with most of your opinions, but here's where I think you're wrong. Those people are not lazy, they are dopamine addicts. Or, if you prefer, simply addicts - as all addictions seem to be about dopamine dynamics after all. Food becomes the favorite source of "satisfaction" (experts could provide a better definition) and through the vicious circle of addiction, it tends to become the only viable source. Overeating is a behavioral addictions which happens to have obvious, visible consequences - as such it's a strong source of shame, which itself is part of the addiction cycle.
Overeating isn't the only cause of obesity. Some people just have poor diets and don't exercise. I had a friend who was overweight, who only ate like twice a day, but his choice in food were lousy and he would spend most of his time playing video games.