why are so many people fat when all you have to do is sometimes not eat despite being hungry?

Because people think you lose weight by not eating despite being hungry. That sets in motion a cycle of getting fatter and making it harder to lose the new and old fat. We have an odd way of thinking about food and living in the modern West. We sit around, eat crap, then want some magic spell to make us pretty by losing weight. In a Simpson's joke, Angus Skinner says to the grocery bagger "I want it all in one bag but I don't want the bag to be heavy." He doesn't think that's possible so she asks "what are you, the possible police?"

I am the possible police and people doing everything to get fat and sick and then expecting to not get fat and sick is why they are all fat and sick. Another pop culture reference, in Dawn of the Dead, after being trapped in the mall and acquiring stuff, draped in fur coats they say "what have we done to ourselves?" Forty years on, that scene is the norm so we don't know to ask the question.

So many people are fat because they think they can pig out and sit around then diet for a week and be "saved" so to speak. If all suffering is caused by desire, the desire to be thin, pretty, normal, loved, etc is what causes suffering. Then they eat their feelings and go on another stupid fad diet.

Too many calories, not enough exercise. Weak, lazy.

Because food is tasty and tasty food causes you to be hungrier and want to eat more.

When I was eating garbage I was constantly hungry. Being miserably hungry and having strong cravings makes it easy to pack in the calories. When I eat healthy I'm never hungry even when I only eat 1500-1800 calories.

Some people have medical problems or take meds that cause weight gain but the majority don't.

EDIT: Since you mentioned you bulk and cut I just want to add that not everyone has the will power, time and motivation to be quite that strict and into exercise and diet. Its no excuse to be 100+ pounds overweight but not everyone needs to/should be lifting 3-4 days a week and count calories and macros to become super fit and lean.

not all people get fat from eating

Some have medical issues and take meds that make them put on weight, like taking steroids for cancer or they have a thyroid issue. You are highly uneducated and judgemental, other people's lives are none of your business. What works for you doesnt work for others. There are many many issues that cause obesity in some people. You expect everyone be uniformed? That's impossible! Get a grip.

I am not trying to be rude. I myself each and every day have 100% control over whether I am bulking(adding muscle) in caloric surplus or cutting(Losing fat). It is very easy for me to control weight and therefore I wanted to know why is it hard for others

why are u so rude?