Feel free to ignore the entire history of why the word is here in the first place.
Ideas (untrue, immoral, and poorly reasoned) were how he came to the conclusion that he should kill, but nothing
made him choose to kill. I would venture to bet that given the raw content of his mind, if most (if not all) of the people in this thread were stuck in his head, they would not have made the same choice.
1) Choices are made in a context. The context consists of information acquired from the world outside of the mind, evaluated and organized by the self as it chose to.
2) All people have the choice in front of them to kill or not in any given moment. It doesn't make them born killers. Most people aren't wrong enough to make the choice that this man made. Many would not make it, regardless of how wrong they became. Some would do it knowing full well how wrong it is. Some would do it only when it the right thing to do, and would be right from stem to stern.
3) Human nature is free will. Nothing makes anyone do anything, unless they are physically forced to do it. Choice and force are opposites.