Even after the strike, the CIA, of all organizations, were far from callous in their approach to the bombing. When they saw that six, not four bodies were removed from the building they had just wrecked, they investigated. They spent weeks "poring over drone video feeds, satellite data, electronic intercepts of cellphone conversations and informants’ reports" to analyze the evidence from the rubble, and then quizzed people on the ground about who those extra bodies belonged to.
Once they realized they had killed two "Westerners," and that one was an American (bad) and another not (embarrassing), the Obama Administration did not cover up the ugly truth, but faced it. President Obama apologized even before anyone else called him on it.
Haji Mujtaba/Reuters http://www.nytimes.com/2015/04/25/world/asia/cia-qaeda-drone-strikes-warren-weinstein-giovanni-lo-porto-deaths.html
It's not despite this meritorious conduct, but because of it, that the drone program is a problem. Any time one man -- even a conscientious, intelligent, and deeply moral man like President Obama -- takes it upon himself to be prosecutor, judge, and executioner, he is likely to kill innocent people. No standard to which he can hold himself will be a sufficient protection against results as bad as these.