Around 25% of prisoners (in the USA) are psychopaths which means around 75% are not. Those who aren't obviously have very poor judgement, impulse control and morals but also are very likely to have grown up in poverty, in dysfunctional families and, yes, been abused.
Everyone likes to think well of themselves and one way prisoners try and regain some self-esteem is the "prison hierarchy" which is not something made up by mumsnetters but documented by many sociological studies.
Child abusers and rapists are at the bottom of the hierarchy and other prisoners gain status and feelings of self-worth by showing contempt for them and, as has been seen many times, attacking them (Jeffrey Dahmer).
My sympathies in this case are not with the child abusers and rapists. I would feel the world was somehow worse and justice less served if the torturer/murderer in this case could live out his sentence in a comfortable and pleasant Norwegian-style prison.
Knowing that he will spend his sentence despised and in fear is not something that worries me a lot. He deserves it, Sara didn't.