You're not getting it. With hindsight, you can always find a way to blame a victim. It's great fun: you get the chance to look knowing and smug, and your success rate in predicting the past is 100%.
Don't kick people when they're down. You end up looking like a heartless jerk.
He's not a victim of a random crime (per your analogy, which to me is not apt), he's a victim of his own naivete and inexperience.
In the same way you had better know to take all of your most expensive gadgets out of your soon-to-be ex-girlfriend's apartment before you break up with her (lest they get smashed with a hammer), he should have done the same.
This is not even close to rocket science. To assume that people will behave like adults when you sever a relationship with them is extremely naive.