Being overweight does not equal gluttony.
Not everyone has the same genes, metabolism, knowledge of nutrition/diet, or lifestyle. You need to broaden your horizons. You are extremely narrow minded.
You can be a glutton and be completely "fit" with an ideal BMI. Meanwhile, some who are obese are extremely disciplined and never eat junk or overeat.
Yes, there is some overlap there, but it's not 1:1 or something you can assume.
When you get a bit older (grow up?) you will discover this for yourself. Apparently you haven't experienced the world very much yet. Your view of reality seems to be extremely narrow and limited.
In fact, I'm going to say "Just wait until you get older". I used to be able to eat whatever I wanted when I was young too. I had zero compassion for the other side. Well, this is probably my punishment, having to deal with know-it-all youngsters like you. Now I know how foolish I was.