I'm exhausted by the coverage of this and the constant "OMG where did the world fail these boys? What went wrong?"
When I think of situations like this, I think about a computer factory. A really great computer factory. And let's say the factory churns out 1 million computers per day. Even if it's a really excellent computer factory and everyone works very hard and the technology is sublime, some of the computers will just not work. They will just be asshole computers with faulty circuting. We shouldn't point fingers at the factory owners or the people working in the assembly line; some computers are just not going to work.
Likewise, some people are just destined to be horrible, horrible murdery assholes and nothing can be done to save them. They're the lemons of humanity.