karma
He raped people (apparently more than once) and was punished, and he served his time. Does him being in jail make the rape victims feel better? How do they feel when he is let out? I think I can make an educated guess on this.
Now he is a victim of a crime, and the person who did it will (probably, hopefully) serve their time too. I don't have a lot of sympathy for the murderer, but I also don't have much for the rapist. Both thought themselves above the law and above other people. Both did something very wrong.
My sympathy is for the rape victims. And I would be GLAD if what happened to this rapist makes someone else think twice about committing rape. Even if it was a mistake, it can serve as a deterrent. What goes around comes around - karma.