In spite of the media's focus on Mental Illness "a deranged person" as the cause, or leading the population to believe it to be the cause, Mental Illness* is not a Rage Shooting Factor or the cause of this crime. Guns are not a Rage Shooting Factor either but a defenseless population does leave it more vulnerable to abuse, subjugation, and oppression (Marie Antoinette).
(*PTSD a possible exception)