Well, it obviously was secret initially as it occured prior to the D-Day invasion, and information about it could have given away the location of the Invasion of France.
But there WAS NO POST WAR COVERUP. It was declassified after World War II. And the US Army's official history of the Normandy Inavasion, published in 1951, mentions it.
It's just that nobody noticed it, and of course the Army didn't fall over itself to publicize it, so some not very bright types came along in the 1970s and decided there had been a "cover-up."
If there was no coverup, why has my 93 year old neighbor who was involved in the mission unable to get any information about his service for Operation Tiger.
I true slap in the face to someone who served on the mission, survived his LST being bombed, and subsequent 2 month coma.
Sign me up!!!!