Daleks are sentient life forms that have turned themselves into robots. This is not due to the mechanical devices they live in but because of their inability to do anything but follow their insane programming. They cannot think outside the tank. The Doctor refers to them as evil refined as engineering. Yet are they inherently evil? It would seem they are not if Clara and the Doctor are able to change a daleks attitude by allowing it access to suppressed memories and expose it to philosophies outside its own cultural programming. The dalek is not so much evil as trapped. The Doctor asks Clara if he is a good man but that is not the right question. What is good? Right and wrong are often situational. You cannot judge an action without context. The Doctor is quick to condemn the soldiers but he does not know them. Perhaps they are as unfathomable to him as he is to them.