The trouble is that you get rapists and murders from all backgrounds - your rich wealthy elite, to your middle class, to this guy. I dont agree that his background predisposed him to rape but I think it predisposed him to violence.
However, where does that stop? Should we let him go because his environment made him do it? Should we let him go in a year, free to rape again, because of his environment?
You cant change his environment over night, so as difficult as his background might be, the law must apply to him equally as it applies to others. When you start playing favourites according to background (ahem, AA), you are heading for trouble. That means he has to take responsibility for his crimes. It would be great if it were a perfect world and no one came from a background like his, but, equally, everyone makes choices about their lives and has to live with the consequences. He chose to commit this crime for a cellphone bill. He bears ultimate responsibility.