In the interview Hasejima stated: "The vulnerability of the network was a known vulnerability, one known of in the world. But Sony was not aware of it... was not convinced of it. We are now trying to improve aspects of it."
“We thought we had taken enough management and control measures (to ensure the network was secure), but looking back, there might have been room for further enhancement,” Shiro Kambe added, “We have to admit we were not fully sufficient.”
Even forgiving the shortsightedness of the lack of proper security and fooling themselves into thinking it was sufficient, the question still remains: when Sony realized it had been hacked and millions of user accounts were compromised, why were they silent, shutting down PSN without reason then finally admitting a week later to people their credit cards might or might not be secure?
The word is "hubris".