Funny you seem to approve of things like that when it's the Syrian revolt being crushed. Military action often kills indirectly such as in a starvation siege or an aid convoy bombing. The R+6 in Syria has probably clocked up over half a million civilians killed counted that way. But no matter this is pointless whattaboutery.
We don't tend to count the incidental deaths. Maybe we should. We should think carefully about killing people by whatever means. The strangling sanctions on Saddam's Iraq probably caused much more excess morbidity in that period than any military action back then. You can make that an argument for regime decapitation based on that. A bad one but I've seen it done.
What airpower is for is killing people and destroying enemy infrastructure. Our laws of war allow a lot of very nasty behaviour including killing civilians. If it's a "command centre" you can bomb it. In Libya that was any head Qaddafi might have been crapping in. It's what you do mostly in state on state wars. Though we are not shy of bombing IS infrastructure and supply lines that civilians in the Caliphate rely on.
American COIN doctrine is really a very different approach that evolved over the Iraq war. The elaborate reference manuals like
FM-3-24 are available. It's this way not because of any innate moral superiority but because cruder methods failed to reduce a peculiarly savage insurgency. They actually increased it. It took half a decade to evolve in places like Tel Afar and Ramadi. I remember reading a bootleg CIA manual from the the El Salvador period. Killing the voter (elaborately) wasn't so frowned on then much like Old Skool Russian ways we see now. Looking at our wars is arguable if this 21st century innovation works. It's rooted in Frog
tache d'huile shit taught at Westpoint that failed as well but there it is.
US military doctrine unlike law or the moral compass of the public is real hard to shift. There is a
precedent: the US Army clung to doctrine and tactics designed to hold up a vastly superior Soviet tank army in the Fulda Gap all through Vietnam. Yes those daft, kinetic search and destroy missions on a sea of Hueys. This was despite repeated harsh Presidential pressure demanding population centric programs like the pretty successful COORDS that the Army Staff systematically undermined. It's been blamed for the US losing that war.
Hence my view of Mattis as a restraint to Trump's amour fou with atrocity.