@SummerEve sometimes wider context is not important. It's individual cases and people that count. I think it was Colin Pitchfork who raped and killed and then was freed. He shouldn't have been. It's much better for society to be rid of him. I care no more about rehabilitating him, than he does about the safety of women and girls.
Who doesn't already know that kidnapping young girls, raping them and killing them is bad and you shouldn't do it? "Oh sorry guvnor, I didn't realise". Rehabilitation my arse.