The military has a VERY tiny percentage of folks that "want" to go to war - and I'm talking about 200 people at the VERY most... and normal folks call them PSYCHOTIC. The rest of us would LOVE it if we could do an entire career and never have to fire our weapons in anger... but the politicians tell us to go to various places and do their bidding. We train for it, but we don't WANT to do it.
We, as citizens and human beings, have to accept that the people that Congress sends us to deal with MUST be dealt with and DESERVE to be dealt with. If fortune smiles on us, just our presense will make them put their weapons down and nobody has to shoot anyone. Unfortunately, that's not the way it usually works.
WHILE engaging the enemy - and please note my use of verbiage - they are merely targets that are either "neutral" or "hot" (shooting at us). We default to our training at that time, because it honestly _IS_ inhumane to kill another human. Once things settle down (usually after a deployment), THEN we turn those targets into humans - and THEN we geet hit with PTSD and problems readjusting to society.
As for drone kills - if you actually knew how many layers of approval a simple missile launch takes, you'd be amazed. A good friend worked at the Pentagon and did the THIRD layer of approval - and he said there was at least one more above him. So, when the soldier on the ground sees a target, a drone has to be sent to film the situation. Then the request for approval is sent up. If Brigade approves the strike, it is sent to Corps level for approval. If THEY approve it, it goes to the Pentagon (keep in mind that the Pentagon is 8000 miles away). Once the Pentagon approves it, it goes up for one more level (at least). If THEY approve it, then the drone gets into position and fires.
Right now, the "acceptable" number of collateral damage casualties is ZERO - but it used to be more several years ago. Depending on the "value" of the target (bin Laden, whomever), the approving officials MIGHT decide that the extra deaths were acceptable.
What the bad guys are doing now are keeping children in their hideouts - entire families. So when Hussein bin Badguy goes into his fortified bunker all alone and we issue the order for a drone strike, the Taliban and al Qaida get to rightfully claim that 30 children died in a drone strike. We do EVERYTHING we can to keep from having civilian casualties - but there have even been times when the request for a strike is sent and in the 30 minutes to AN HOUR that passes before the order is given, non-combatants may have moved closer, or the target may have gone to the market...
Go ahead... come up with a better method to eliminate people that have vowed before their deity that they will kill all Americans in their country and they are actively planning to make that happen. How will YOU eliminate that threat?
I retired after a long military career and several combat deployments.