Earlier quoted context omitted.
A system that does not incarcerate anyone for any reason would be much preferable to the atrocities that are the current criminal justice systems in most of the global west (and especially of course the United States).
Interesting and unusual perspective - we have the one person in this thread who supports wildly expanding the death penalty. Unless the person above is, of course, an anarchist who has no answer for what to do about Richard Ramirez, Ted Bundy, Jeffrey Dahmer, Phillip Garrido, or Brian Mitchell. I would say that as imperfect and heavily flawed as our system is, "Perfect is the enemy of good."
Nothing. Those people are one-in-a-million anomalies. If it weren't for the media hype surrounding them, their impact on society would be comparable to the impact of deaths from lightning strikes. What do we do about people being struck by lightning? Nothing.