What do I mean by that? Well, the urge to get revenge is an extremely strong part of the human psyche. We really want to see that those who wrong us wind up suffering for what they do. If someone wrongs us, our first instinct on the caveman level is to go over to his house and kill him.

Now, all this private killing tends to cause major problems in society if everybody is trying to individually punish everyone who wrongs 'em, so we outsource the whole "revenge" thing to the government, who sets up a criminal justice system to determine who actually deserves to be punished and then punishes them. You steal my bike, you go to prison and suffer, my bloodlust is satisfied, everything is cool. I don't have to kill you, which means your brother doesn't have to kill me, which means my brother doesn't have to kill him, and society is a much better place.

Now, in order for all this to work, we need the "revenge is bad and uncivilized" meme. This is the meme that discourages us from taking private revenge against people and tells us we should really just take it to the police. And that's fine and dandy, except some people seem to have generalized this from "private revenge is bad" to "all revenge is bad", and have started claiming that the justice system shouldn't be about revenge or punishment either.

I've gone on a bit already, but my main point is that the primary goal of the criminal justice system should be the satisfaction of the natural revenge-desire of crime victims, not necessarily the absolute minimization of the crime rate.

edit: Also, surely there's some fundamentally funky statistics going on with the "lowest reoffending rate" thing? Presumably prisoners are not assigned to this prison at random -- only the least problematic prisoners are allowed to go there.

I don't think that's currently an emphasis outside of a handful of countries with extremely liberal views on the matter, Norway being probably the most extreme case. In the U.S., for example, punishment and a desire by politicians to appear "tough on crime" seem the main factors. I certainly don't think sentence lengths are calculated based on statistical evidence about which sentence lengths would actually be most effective in reducing crime.

I'd make the opposite claim, myself: I think the present emphasis on prisons as solely a form of punishment is misguided. In particular, I have no interest in my money being used to subsidize somebody else's desire for revenge. I'm okay with paying a minimal amount of taxes to lock people up when absolutely necessary, but I'd like that to be scientifically determined so people are locked up in the most cost-effective way, when actually needed to deter crime and reduce recidivism. But paying into a "socialized revenge" public subsidy? No thanks.

This rather pessimistic assertion (which to me is reminiscent of Christian dogma) needs some backing up.

http://www.unl.edu/rhames/courses/war/diamond-vengeance.pdf

It has nothing to do with Christian dogma. In fact as the OP asserts, most religions/social systems attempt to control the individual's desire for vengeance.

About the statistics: The avarage rate in Norway is 20%. In this particular prison 16%. Nothing funky about the 20%.

I'm certain it depends on whom you ask. The ones who would seek revenge most fervently would be direct family members. They are currently in mourning.