It can both be overly simplistic and also true enough for large portions of the population. Not unlike BMI as a metric where in aggregate it works and for most

It can both be overly simplistic and also true enough for large portions of the population. Not unlike BMI as a metric where in aggregate it works and for most people it's a reasonable approximation, but there are outliers for whom it makes no sense. Too many people like to point to the "yeah but's" on this topic when their underlying problem is that they eat too much and move too little. And then yes, there are people who have already fine tuned eating less and moving more and aren't seeing the expected deltas. Those are the people who should be worrying about the details. But for that bulk population it just turns into an easy excuse.