We did *not* follow this mentality in Iraq when we went in, and we're still not. We went in with a surgical approach, and that can't work past a victory against the government and the military. Following the same approach would mean if snipers are holed up in an urban neighborhood, you fucking level it. Rubble on rubble. Need security? Demolish square blocks around whatever you want to protect, bulldoze the debris, then pave it over. Leave no place to hide for anyone without clearance. We are not doing that. If we were on a scorched-earth campaign, why do rogue provinces under hostile-warlord control still exist?
You can pinpoint terror to an ideology. Attacking that ideology where it lives is feasible. We didn't eliminate the threat from fanatical Japanese by killing every one of them. We engaged in attitude readjustment. The problem isn't the people on the streets of Iraq or wherever chanting and shaking their fists. They can do that till doomsday, and we'll be fine. The problem is the powerful organizations giving them AK's, bombs, travel papers, money and targets. What they care about is what we have to hold hostage.