If it was easily preventable there wouldn’t be rising obesity
Weight loss requires a calorie deficit, and the average person has no training or education for this. Why would you expect them to be good at something they've had no education or training in? 40% obesity rate is not surprising when no education/training exists for average person.
People are fat and lazy. It's not that complicated.
I'm not sure why we have to pretend they're not and blame the rest of the world or point out random edge cases.
you're treating obesity as a moral failure which is not helpful to the people with the problem, not really supported by science, and frankly a not great position to hold in general. Stop thinking about "blame" in the context of health issues and maybe try to see what helps the people who live with those issues.
Again, you're making a mess out of nothing. Nobody cares why, but they need to put the burger down. Simple as that.