The People want an enemy crushed, like what happened to the Germans and Japanese. The meat and bones of COIN isn't going to sell on the home front, no way. It's sort of a 'we're paying out the nose for you to be there so show us dead enemy' type thing. I think there is a very subtle, unspoken fear over the idea that to understand an enemy, one must be able to assume some of their beliefs and values. Mom and Pop back home don't want to have to be able to think like a jihadist - they only want you to eradicate the threat. That's what jumped into my mind.