So? Of course the criminal justice resources are being used but at the same time there is a long list of transgressions that if they weren't a response to terrorism would invite just that.
> And I think the question of how to fight armed combatants in remote areas of the world is a real moral gray area (really: how many people should die to apprehend someone committing crimes of this type in a remote area of the world?
It's actually really simple, and not morally gray at all: If you can name your foe then you ask kindly for the nation where the foe is hiding to extradite them so they can be put on trial. If that fails then you're out of luck.
> The law enforcement/military people that would do this are 3-dimensional and their lives count).
This is the basis of the doctrine of 'force protection', worthy of a chapter all by itself and in many ways a substantial part of the problem. American lives are not worth even a little bit more than the lives of people of other nations.
So, in short: getting your hands on the perpetrators of terrorist attacks is roughly as hard as getting US 'contractors' extradited from the United States to Iraq for the crimes they committed. And that means that if it does not work you do not have an automatic 'ok' to go and kill those people because that makes you stoop to the level of nation state sponsored terrorism, aka acts of war.
Fortunately there's been detailed study of counterinsurgency since the end of WW2, looking for the most effective strategies, e.g.: https://www.rand.org/pubs/research_reports/RR291z2.html
"The "iron fist" COIN path, focused primarily on eliminating the insurgent threat, is historically less successful. A motive-based path (one that focuses on eliminating the incentives to support or participate in an insurgency) has been much more successful."