So, as I said, I reread Dunlap's article a few days ago, and noticed that it was a lot more faceted than I had previously thought. However Gian Gentileargues that by focusing too much on COIN, we are losing our ability to fight conventional wars.
Now, we will leave the prospect of ever fighting a conventional war again on the side for right now. Let's just assume that it is, indeed, a possibility. A COIN fight is characterized by much harsher restriction on the abilities of soldiers to lay down overwhelming firepower than in a regular war. (Yes, there are lots of other things, but this is my analogy). Soldiers need to restrict their responses, learn to think about more than just overwhelming force, and (this is something frequently overlooked by supporters and detractors of COIN) take more risks and expose themselves to more danger. Now this last is a good thing, by the way. You can't have a commanding officer say to his men: "We're gonna go out there, kick some butt, and accomplish the mission, and everyone's gonna come home alive." It is an unfortunate fact that in war people die. But, when you place equal value on living and accomplishing the mission, neither is going to work out well.
So, that does all this mean? First of all, COIN will teach soldiers and commanders to take risks. Powell doctrine aside, that's what it takes to win, whether in COIN or in maneuver warfare. Great generals have never been made by taking the conservative approach.
Second, soldiers are conditioned to restrict their responses. Sure, SLA Marshall had some things to say about teaching soldiers to conserve ammunition and therefore not firing in combat. All very good points. But, and this is where we get into Messrs. Deleuze and Guattari, it is much easier to remove the restrictions on people than it is to try and enforce them. Soldiers learn to fire every round on single shot. But given the opportunity, every soldiers lives for the few moments he will get to fire his weapon on burst or auto. Rock and Roll, Let Loose, and Get Some! And don't think for a moment that soldiers on the roads don't completely bypass the "Semi" marker on their M-16s and go straight to "Burst" when someone starts shooting at them. We don't have to worry too much about soldiers NOT crying havoc when the opportunity presents itself.
Thus, learning COIN doctrine, and fighting the COIN fight, teaches soldiers to act within certain prescribed limits (which, I would also argue, Basic Training and regular warfare does too). Teaching them to not have those limits, and then trying to enforce them, leads to things like Abu Ghraib, Haditha, and My Lai. Rather, enforce the limits from the beginning. When the time comes, it will be much easier to let slip the dogs of war.