Speaking from experience, that assume that you are currently maintaining your weight. I think a lot of people are gaining weight slowly, so burning those calories actually just keeps you at your existing weight, not decreasing it.

It's also really hard to not overeat after working out, especially if you do something like swimming, which makes you just so hungry. The hunger reduction is I'd like to try ozempic. I am active (I swim 3-4k yards hard 2-3 times a week and surf once a week + walking generally), the hunger I have after swimming is so huge I just can't not eat something huge, even though I drink a ton of water and do all the other things people say to do to not get hungry.

I've been a lifetime swimmer, so I can relate. There's a reason a lot of swimmers and waterpolo players gain tons of weight as soon as they stop training.

Usually if you can fight through the "hunger" it'll calm down in its own after about an hour or so in my experience.

Right, but the exercise made OP eat a protein bar, which has about as many calories as you were burning in exercise.

The exercise made OP eat a protein bar?

I feel like you just inadvertently explained why dieting is not the answer.