Notice the wording - the drone targeted the workers. The drone didn’t make a decision and target the workers, the drone pilot targeted the workers, and whomever was standing behind them gave the order to launch the missle. The whole “I’m just doing what the computer said” defense only works in movies.
It doesn't work even in the movies. Last American movie I watched which featured a drone strike against civilians, involved an advanced AI that recommended not to proceed because of insufficient information, that got overruled by the president. The drone strike hit a wedding, which led to increase in attack on Americans, making the AI attempt to kill the president and most of the US government, following the "protect against all enemies, foreign and domestic" doctrine.