Until you can come up with a viable, demonstrably effective non-military approach to eliminating threats like that, we will continue to need a military capability. I speak as a Brit, about the wider 'we'. British troops are operating in Afghanistan right now, some of them are even Muslims. We're standing by the US, yet we have Americans here advocating undermining your own military, putting US and foreign services lives in greater danger, so they can feel a smug sense of moral superiority while sipping their skinny lattes in a nice comfortable office, just like the ones incinerated in New York in 2001.
Wars are horrible messy affairs. Innocent people suffer. It sucks. But advocating pretending threats don't exist and it's not our problem without addressing the actual issues is an utter abrogation of moral responsibility. Western militaries have gone to huge lengths to improve intelligence gathering techniques and achieve more precise targeting, massively reducing civilian casualties and blue-on-blue incidents. Surely supporting such technologies and programmes is worthwhile?
It's not clear that they conspired [0], though I suppose you could call them an accessory after the fact for refusing to extradite bin Laden.
[0] https://en.wikipedia.org/wiki/Responsibility_for_the_Septemb...
That's not only morally repugnant on its face, it's flatly untrue. Greater collateral damage has rarely if ever prevented war. Past wars with high collateral damage have been longer, costlier, and more frequent than they are today.
Even if your utilitarian analysis were stomachably close to moral (it's not), it would still fail any sort of empirical test.
I personally find this line of reasoning quite compelling. It's pretty clear that precision guided bombs, drones, body armor, and other technologies designed to save lives in war have also made war much more politically palatable for the DOD.