It seems to me, and this is just my generalized thoughts on interactions with fellow officers, that the people who study war the most and take theory and strategy the most seriously are the most strident proponents of population-centric COIN. Take McChrystal and Petraues, they are frequently regarded for how intelligent they both are and their impressive amount of reading. Look at Kilcullen and Nagl, they are some of the smartest and deeply read in the field of contemporary historians.