That's what happened the
last time we found him (we tried airstrikes before) and it wasn't because we were worried about killing civilians, it's because we needed the job done, verified, more-so than your average middle-ranking terrorist.
Also, not an easy task to fly a Navy SEAL team around the world constantly to do operations like this. Not only does it risk their lives, but sometimes it's not even possible to get there physically or in enough time.
Also, somehow the terrorist were able to recruit before the US and it's allies "retaliated" with drone strikes. Sort of a chicken-and-egg problem but it would be crazy to blame terrorism on the killing of civilians that only took place.. because of actions of the terrorists.