Why did James Holmes do it? Why did he plan and execute a massacre of innocent people?
Based on the information that has so far come to light, it comes down to two things. (1) Because the person he loves in this world more than anyone else is himself. (2) Because he wanted others to experience the devastation he experienced when his dreams of a great life were smashed.
Like the Joker of Batman fame he announced himself to be, James Holmes saw himself as a victim. Victimhood is the perennial backstory of countless acts of violence. It is the backstory to this one as well. Holmes knew that it was not his fault that the life he dreamed for himself was taken away from him. He wanted to take away from other people the same thing that was taken away from him: a future he could believe in.
James Holmes wanted to have a happy life. When he became unhappy to the point of not seeing how he might become happy again, he was overcome by a desire to make others share his experience of devastation and defeat. He continues to be possessed by that desire. That is the only explanation for his lack of remorse for what he did.
Like Anders Behring Breivik, the Norwegian who killed 77 people not long ago, James Holmes cannot be described as out of his mind. On the contrary, like Breivik, the Unabomber, and many other mass murderers, he lived inside his mind. He was a hyper-intellectual.
James Holmes is like us in a thousand ways. The only way we can protect ourselves from the demon of loving oneself more than anyone else is to recognize sin for what it is. In the words of Martin Luther, sin is the fact of being incurvatus in se, curved in on oneself.
The best way to avoid sin is by not playing the blame game to account for our shattered dreams and our bottomless misfortune. The best way to avoid sin is by living by the questions God, who is the sum of all that is true, good, and beautiful, has posed to humanity from time immemorial.
Here is a short list of places where such questions are found: Genesis 3:9 [“Where are you?”]; Genesis 4:9 [“Where is your brother?”]; Jonah 4:4 ["Are you right to be angry?"]; Job 40:8 [ “Do you condemn me that you may be in the right?”]; Luke 6:46 [“Why do you call me, ‘Lord, Lord,’ and not do what I say?”]; Mark 8:29 [“Who do you say that I am?”].