Blame the victim is never a good argument.
That's what this whole thread is about, blaming the victim. Assuming OP is true, then Bitcoinica is the victim of a theft. Everybody here is blaming Bitcoinica, not the thief.
If I'm holding $100 that is yours and I get robbed, I'm the victim if I pay you back your $100 out of my own money. But if I say to you, "sorry buddy, your $100 is gone, I got robbed", then *you* are the victim.
Fair enough.
But not being the victim doesn't make you the criminal either...