Society has not failed some people. A person for whom all mental and physical faculties are intact, yet is simply evil (these people do exist), who goes on to rape, murder, engage in paedophila... these people have failed society and should be removed by dint of a rope.
There are cases where people have been overlooked, needed help, etc. But the evil among us should be purged. Locking up serial rapists, serial paedophiles, and serial murderers does nothing but waste taxpayer money. If someone who commits these crimes is found guilty beyond any shadow of a doubt, they should be removed from society.
Norway, for all its goodness, needed to execute that moron who murdered all those kids in cold blood. Yet, he enjoys an expansive room, cooked meals, TV, games, conversation... all like it's no big deal. I think that is an example of society failing to deal with a problem. There is no closure for all of those families who lost innocent children. They exist knowing he exists, and is enjoying life as he's able.