I think the take home point is that people need to figure out their nutrient rate based on what their activity is.

This is true but only in an indirect way. Mostly people need to retrain their bodies how to utilize stored fat when they're not eating. This will naturally make them eat less calories but also improve other metabolic pathways in the body. It's less about the quantity of food we are eating and more that we eat too frequently and we eat too many foods that act more like addictive drugs then nutrition. Some foods straight up damage our metabolic pathways and until we get that fixed we can't lose weight. The chemical signaling in our body is very powerful and often overides the simple input of 'less calories' or 'more activity'.

You can only burn so much fat or build so much muscle, so you need to ensure that your nutrient rate is conducive to whichever goal(s) you have.

Individuality is certainly important. Lots of generalize diet advice, even the more modern stuff, is totally going to need changed if you are very sedentary, very active or you have certain genetic markers. Even race matters here but our food 'scientists' would never openly come out and say that. It conflicts too much with the old liberal values that we are all the same under the skin.