The Navy needed more navigators than they could train and keep? And the Coast Guard had more than they needed? That’s irony tor you!
I think some admiral “liked” him and stole him. Even if he had been inducted into the Navy, he was probably doomed to be a navigator. His personality may have made him shun command, but command is a skill that can be developed. Even commanding a small detachment of channel marker maintainers prepares you for bigger things. Sweating over charts just makes you a technician. He was good technician.