And yes, the crackers are to blame, but in all honesty, not as much as Sony are. Sony are a multi-billion dollar corporation, and should have known better than to as someone so kindly put it, "leave all the windows open and doors unlocked." If you think they're less guilty than the crackers, then you sir have a mindset that scares me.
That's not reassuring considering that being atheist means god did not create any green apples, but rather they evolved into apples over time. In this case, Sony should evolve over time and start doing shit the proper way, and legislation should evolve to make sure corporations like Sony cannot half-ass protecting your personal information again.