CIA, US army - does the difference really matter? Maybe I should just say the US from now on.
Come on Helgo, you're better than that. This is obviously a false choice. First of all, most of the drone strikes are run by the CIA, not the military. But more to the point, any actions involving missiles and targets will run a risk of killink civilians. Each institutions has to decide on the proper equilibrium between "killing targets" and "risking civilians' lives". In both Israeli and US strikes, I think it's fairly clear the balance is way to much on the "killing targets" side, using dodgy practice and secrecy to hide the true result.
Looking back, I may have read more than was written there, but I'll try to answer regardless.
Yes, it is about the balance between civilian casualties and military impact.(
Not killing targets! When killing an enemy soldier the acceptable (oh God, that sounds horrible) number of civilian casualties is much lower than when killing an enemy general.) Do we know how many civilians are really killed by drones, and how great their military value really is? No. Do we know what that balance looks like? No. Do we have a nagging feeling that it's not where it should be? Definitely when talking about drone strikes; we shouldn't get into that whole Israel discussion though. Does the US intentionally target weddings or similar gatherings without military reason? No. Are the majority of drone strikes conducted against weddings or similar gatherings? No. That last bit was what I wanted to emphasize. The secrecy surrounding drone deployment does not help in allaying suspicion, of course.
Of course, in the US case there is the further issue that they launch their missiles at nations they're nominally at peace with. Even leaving collateral damages for a moment, don't you see a problem with the fact that the US executive basically decided it had the right to kill anyone anywhere without any real oversight?
The concept of war as we know it - between sovereign states - was codified in the Peace of Weestphalia. Modern-day armed conflicts no longer adhere to that scheme: Nowadays non-government actors, such as terrorist organisations like Al-Kaida, radical parties like Hamas and Hezbollah, semi-state entities like IS, state-sponsored and -supported rebels like those in Eastern Ukraine, etc etc can wage 'war' on states, that is, use force in a military manner against that state's institutions with political goals. If you agree that the definition of war needs to be expanded to cover these instances as well, you'll see that your question has already been answered: War with an entity at its very core implies that you kill that entity's agents, wherever* they may be.
*This 'wherever' occasionally comes into conflict with the (outdated) concept of sovereignity, like during Operation Entebbe, in Western Pakistan, and in Israel's various clashes with Hezbollah. That's another debate however: I'd be inclined to say that anyone who shelters my enemy must either allow me to pursue him or be considered my enemy as well.