I'd push back on what you are saying by again saying, look to the people that initiated the directive. Like I said before we do not value these moralistic traits as a society. Nazi Germany did, and in turn molded people to do the same. Were these people who admitted to it predisposed to harboring these views than those that did not? I think that is a pretty fair assumption to make. I can link evidence of Nazi Germany troops feeling destroyed from killing that butts heads with that link.But now it has become clear how the Nazi regime dehumanised so many of their own troops
We are creatures of our environment for the most part. I believe currently we (ordinary people) are not predisposed to kill and have been for a long time, but we are definitely susceptible to being manipulated whether its direct or indirect.