Except that's not what appears to have happened here. I didn't see any suggestion in the article that the bank knowingly lent out the money, most likely a human error or bug in one of their systems caused his account to have this line of credit applied to it.

If they had pushed him to take a reckless loan, I'd agree with you that they shared liability here, but this was (from what I've read) just him taking advantage of a mistake by the bank.