The point is pretty simple. You cannot assume the Sheriff is responsible for producing the investigative data he reports. So you cannot personally blame him.
He didn’t have any such “investigative data” when he claimed that he “couldn’t get into the mind of a psychopath”.
UNLV psychology Professor Stephen Benning says it’s human nature to want an explanation for such a heinous an incomprehensible crime, but he’s fairly certain the sheriff missed the mark.