I respectfully disagree with your analysis. We won't pay for it if we are not there. Most of these people are not Islamofascists. They were just people in a city...defending their city. Same as you would do if a foreign army invaded your city.
There were only a few hundred foreign terrorist types there, by the Marines own estimate. The rest were simply Fallujah citizens thinking that they were protecting their city.
It’s too small a post 9/11 world to believe that.