Revenge is of no benefit to society, no question, but it could bring peace to the offended.
I also agree that there are very few Bernardo's, but the fact remains that prison sentences are like tattoos, most people don't get only one in their lifetime. My tenant is a guard at the Milton Hilton, there are inmates that get released and are back in so quick that they don't even miss a meal.
Fact remains that because of the charter of rights and freedoms, inmates have a cozy place to live (relative to other countries) with no real incentive to get their crap together.
In the defense of inmates however, I don't think a criminal record should be a lifetime scar. It should automatically be expunged after a period of time (based on crimes committed and person's history) to help those that really want to change.
The brain is very complex. Revenge and anger are like letting someone live, rent free, in your brain. Shedding that is easier said than done.
We aren't like a herd of wildebeests in Africa. They run from the pride of lions but when cousin Louie gets caught and the lions are eating him the rest of the herds shrugs it off and goes back to grazing.
We never forget cousin Louie. He was part of our life and the void of that part is never filled.
It would help if the perpetrator showed genuine remorse. It would help if the judicial system wasn't as hard on the victim.
Maybe the worst part is that the rest of the world goes on. The guy on TV still wants to sell you a tropical vacation and new car. People still party.
Many criminals are victims as well and to some extent their anger can be understood, just as we get angry at those that victimize us.
What the average mind has a problem with is the person who grows up in a good environment but become evil. They get joy out of cruelty.
Expunging a record is IMO easy for crimes such as theft. If a person rehabs and shows they are getting on well without breaking the law they can be taken as cured. It's different when the crime is more emotional, particularly sexual. I don't know what indicators would define "Cured" with sexual crimes.
As far as general crime perpetrators I can't help but feel that most honest people enjoy things they got from working, a sense of accomplishment. A thief will never feel the enjoyment of working for something. Can a thief be converted?