Let me ask a really simple question - if the court martial happened, and if making it public would have been to Kerry's benefit at the time, then WHY DIDN'T KERRY HIMSELF MAKE THE FACT OF THE COURT MARTIAL PUBLIC?
Because 1972 was still not an acceptable time to be court martialed in the eyes of the public.
Kerry would have forever his record of his court martial public since 1972, and instead, he keeps quiet.
The Navy keeps quiet to avoid making him a martyr.
Kerry keeps quiet to avoid being branded a traitor since 1972.
I think the guess fits the story quite right.