In this version of the future, science has learned how to identify a propensity for violence within the human mind before it manifests as action, and the violent ones have become targets for extermination. This is a humane, disciplined and well-intended social program, and civilization expects its unfortunate recipients to make dutiful sacrifices. Unfortunately, this sort of person is not likely to go without a fight.
In the not-so-distant future, violence among humankind is on its way out. Almost.