Soldiers are directed by politicians at all stages. The decisions on what to do after surrender is entirely made by politicians. Basically an army's job is to break things and kill people. The politicians' job is to know what to do with such a powerful tool as an army. In my experience, precious few of them do.
No, but what's your point? Should we require computer programmers to read books explaining why murdering people is wrong in case there's another Hans Reiser or Ross Ulbritch?