It was tradition... Back then, we valued tradition. It connected us to those who had gone before... Especially the giants who fed Hirohito a steady diet of Mark 14 warheads. We were very proud of being the down line recipients of the legacy they passed on to us. Pinning fish on a wet shirt was a ritual that was a bright link in the chain of the continuity that was the history of the submarine service.
The rationale for the elimination of the 'wet shirt' tradition, as explained to me by a very professionally correct and obviously responsible nuclear submarine officer, was that it involved silly, unnecessary and easily avoidable risk. Sounds right... Only one problem...
American boys of an earlier generation grew up climbing trees, shooting each other with Daisy 'Red Ryder' B.B. guns... Jumping off garage roofs and playing with fireworks one level below nuclear ordinance. Risk was an integral part of the excitement of living.
The acceptance of risk was a primary attraction of the mystique of submarine life. The pressure of seawater on steel hulls at depth has always held risk. People who want to avoid risk, become typists in the Ohio National Guard... They sure as hell don't sign up to ride worn out, World War II submarines.