I don't think anyone is disputing that? The challenge has always been getting people to eat less, not making them realize that is what they need to do.
Oh, but they do, even right here in this very thread!
I admit it's hard losing weight - I've been there. But there are some people who will compound the difficulty of following through by denying the reality of the conservation of mass.
"Eat less food" is technically true, but as useful dietary advice as "become less obese".
Those reasons still add up to Calories in - Calories Out. You need Out to be > than In or you will not lose weight. Eat all the kale and celery you want if you aren't burning more than you eat you won't lose weight.
and forcing people to exercise just gives them ravenous insatiable hunger. if they're not aware of this they'll reach for the carbs, ruining all their work.