The morality of this targeted assassination policy is absolutely a valid topic of discussion, and I have to agree that it’s a troubling policy. But there is no doubt whatsoever that the targeted people are terrorists who would commit mass murder if they could, and the alternative to targeted killings is a wider war, in which many more people would be killed including innocent non-combatants.
This seems to me to be the best solution in a morally murky situation. If there’s ever any evidence that these expanded executive powers are being abused, though, all hell will break loose.