Most obese and very overweight people cannot sustain the output of 700 calories an hour, cardiovascularly (spelling) or with the state of their knees and muscles.
Also, it’s very easy to eat an extra 700 calories especially if you are in the “I worked out so I deserve a treat” camp.
Your lack of understanding comes across in your stance as well as the attitude.
Yes exercise is fantastic for your quality of life years and all cause mortality, but it’s not the whole story.