Comment 4 by ccw95005 :

Of course in the real world, we look at the perp, and show mercy or vengeance at least partly on the basis of whether we like him or loath him.

However liking and loathing is absolutely corruptible in the human brain: see same sex hatreds or gender enslavements or class derision everywhere. Perpetrators are sometimes even raised on high as leadership, promoted to position where their next generations progeny will be afforded high rank and privilege for the duration of whole lifetimes and beyond. There is no morally incorruptible position per se. Even hatreds are often that which they claim to loath: a desire to harm and pain another. Retribution becomes the perpetrator, so very easily by shades of grey and inherited privilege (often built from perpetrating criminal activities in ones family tree at a time when current laws were not the same or more easily avoided).

Needless to say there are some very nasty individuals, by motive, both to perpetrate horrors for the sakes of deviance and also those who would choose to for the sakes of what they would class as retribution. The distance between the two states of mind is probably less, in neuroscience, than we might wish it to be? The cycle is less one of any holy proviso, and more one of delusions and unpredictable events as they befall each of us. Probably most people who do most things think they have good motive or good elements of complete desperation to explain away what unfolds in the often chaotic situations that are our permutation of life experience. Less of us win any lottery for example! More of us lose, in darker shades, despite gambling everything we have on the life we are in, as is everyones remit!