Well obviously this guy was a crazy person, and I'm not sure I'd want him loose on the streets knowing what I know about him, but on the other hand I believe that most people have the capacity to be rehabilitated, even after something as heinous as murder.
Of course there is no one-size-fits-all course of action in this regard. Some people are not just crazy, but violent and sadistic as well. Those people ought to be locked up in a pitch black cell for the rest of their life or do one better...
Any way, I'm sorry if I come off strong on this one. I'm just irked that this is an article when this kind of thing happens (parole request) to a celebrity killer. I will note a disclaimer here that I'm not a big Lennon fan. He was a much more flawed individual than people remember him as. Not that I hate him or anything, just making the point that even celebrities are human.
FYI, have you ever listened to his sons' music? They sound eerily alike to their father!