This is a masterclass of CYA. He takes a lot of effort to try to prove that the system he was in charge of wasn't the cause, even though his arguments are absur

This is a masterclass of CYA. He takes a lot of effort to try to prove that the system he was in charge of wasn't the cause, even though his arguments are absurd ("if we accept Marriott’s statement that the breach began in 2014, the system would already have been operating securely for five years." It was operating for 5 years but there's nothing to prove that it was operating securely for 5 years.) He also handwaves and leads the readers down some detective story ("ergo it must have been the data warehouse!") and says "We really don't know if it was Valhalla and may never know!" No wonder he's an executive, he is an expert CYA-ers!