It's weird for you to say that "people who have the habits for not being obese aren't obese." What's the real point?

Note that "have a balanced diet" is doing a lot of work here. Our modern environment is saturated with super calorically dense, hyper palatable food. THAT is the cause of the obesity epidemic -- it's not endocrine disruptors or seed oils or office jobs or anything else.

And the ability to refrain from eating cheap processed food, which has been specifically engineered to hack your brain, requires education, discipline, and willpower. As does hitting the gym.

It's not surprising that most people don't innately have this ability, and have ended up sick from it. That sickness is a medical issue regardless of how we got there.