In 1975, under the British 30 year rule many facts about World War II emerged. One was that through most of the second half of the war the Allies knew in detail about Axis strategy and even tactics through Enigma decipherment and that the British had built the first large computer to assist with that.
Many other minor facts also emerged. The fact that they knew details of the design of the V2 rocket and it's range and power before the first one was launched. The fact that elements within the British intelligence groups detected and defeated the German radio navigation systems, that other elements knew just how bad British bomber navigation was but had great difficulty in making bomber command accept it, dozens of other facts.
Luke, who was no fool, realised that after a few generations, or even only one, the secrets of the past are no longer of much actual interest and are often made public.
Again we see people presenting matters of common observation or applied common sense as if they were miraculous revelations.