We still all have human nature and animal instinct. We just all have different points of breaking. Those people you mentioned above, theirs are different than other peoples. It's normal for one person to be different than the other. I will kill more quickly when my daughter is threatened than when I am threatened. I will die more quickly for someone when it is my child than when it is a complete stranger. Different levels. Different people. Different situations. These are things that effect decisions and when a person will revert to animal instinct.
I do what I have to to survive, fuck the law and fuck religion. When it comes down to it I will do what it takes to keep myself and my family going. It has taken alot of getting comfortable with myself to be able to say that.
Morality is more a human trait. Are you saying that without morality you do not have free will? If we really have 'free will', I am inclined to believe that all living creatures have it. But, do all living creatures have morality? If free will is directly tied into morality then there is the question of who or what can feel morality. Sociopaths are said to have no morality. Does that then mean that they have no free will. Wouldn't it then follow that they are not responsible for what they did because they couldn't stop it, it was somehow programed into them? Not saying any of this is so but it is a very interesting thought that I will now linger on for a while. . .