That's a USN tradition, as it is in many navies. A captain's job is a powerful lonely job and there's no one to pass the buck to.
Reminds me of a joke (stop me if you've heard it):
After the change of command ceremony, the departing captain took the new captain to his cabin. He showed him three envelopes, numbered 1, 2 and 3, which he put in the safe. He then said, if you screw up, open envelope #1. He then shook hands and departed.
Sure enough, a few weeks later, the captain screwed up. He went to his cabin and opened envelope #1: "Blame the previous captain", it read. So he did, and all was OK.
When he screwed up the second time, he opened Envelope #2: "Blame the crew". So he did, and all was OK.
When he screwed up a third time, he opened Envelope #3: "Prepare 3 envelopes."
Bad-Dum.