You're treating the human body as a far simpler system that it actually is, leading to drawing unsupported conclusions about the efficacy of exercise as an intervention for fat loss.
I only see that study cited by people who are looking for excuses to not exercise.
At the same time, I keep up with the latest science and understand the limitations of exercise as a means of sustainable weight loss for the general population.
Please stop talking about simple arithmetic - the body is not a simple machine and trying to conceptualize it as such is willfully ignorant.