The issue e.g. with obese people isn't that they didn't have the bright idea that they could "just" eat less or "just" move more — the issue is that there are very often underlying paychological reasons for the way people take decisions. This is not laziness, this is having a personality structure that makes it harder for you to stay healthy.
We all want to be happy, if for some reason happiness for you is tied a lot more to eating than to being healthy and fit, you can try all you want it just wont make you happy if you do. That means tackling obesity means also asking yourself hard questions about what food does for you, how it got that way (e.g. having grandparents which nearly starved can have an severe effect on the food habits for a few generations down the line, sometimes parents can only express their affection through food which means now you equate food with existential parental love). Changing habits is hard, understanding your own psychological drivers and doing something about it against the resistance of your brain is way harder. Never underestimate the struggles other people have to take in order to do the thing that is easy for you.
We all want to be happy, if for some reason happiness for you is tied a lot more to eating than to being healthy and fit, you can try all you want it just wont make you happy if you do. That means tackling obesity means also asking yourself hard questions about what food does for you, how it got that way (e.g. having grandparents which nearly starved can have an severe effect on the food habits for a few generations down the line, sometimes parents can only express their affection through food which means now you equate food with existential parental love). Changing habits is hard, understanding your own psychological drivers and doing something about it against the resistance of your brain is way harder. Never underestimate the struggles other people have to take in order to do the thing that is easy for you.