Drones and robots don't have conscience.

They don't and you cannot program them to have one. You can program responses, calculations; but, you cannot program regret or feelings. You cannot program emotions into machines. That is the nature of consciousness and you cannot create in a machine, you cannot even fake it.

You cannot program feelings into a robot and people are not thoughts, they are a collection of emotions. Helen Keller proves that by discussing what it meant to not have words or a way to categorize or express what she was feeling because even without words she still had feelings and preferences.

Without emotions, true intelligence cannot be achieved in machines. A drone feels nothing, it learns nothing from who it kills other than how to kill them better. It never considers if what it is doing is right or will result in pain. Drones feel no pain so they cannot understand it, pain is an emotion. Computers cannot judge people, they can only follow their program and weigh what they are told can be weighed the way they are programed to judge things. You have to tell them what is right and wrong and we cannot agree on that and there is no objective answer. In fact, if there is no God then there can be no absolute right and wrong.