You're assuming basic rationality of people, which unfortunately isn't universally valid (I have the same intuitive tendency, which I've learned to be aware of

You're assuming basic rationality of people, which unfortunately isn't universally valid (I have the same intuitive tendency, which I've learned to be aware of and compensate for). Disgruntled (usually ex-) employees have been known to do some pretty insane, destructive things, without appropriate regard for personal consequences. What was the name of that guy who locked his ex-employer out of their infrastructure and caused a big rumpus a few years ago, again? More to the point - we know that there exist people who are capable of walking into their workplace with an assault rifle; the existence of a person inclined to execute the attack on Sony should not be surprising.