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.
Imagine being the person (even if you had little personal autonomy in the matter) who pulled the trigger or pressed the button. Imagine finding out what you had done. Would it break you?
It’s as bleak and distressing as you can imagine. Here’s a couple to get you started:
https://www.theguardian.com/world/2015/nov/18/life-as-a-dron...
https://dronecenter.bard.edu/burdens-war-crews-drone-aircraf...