Your knowledge base is long out of date on this subject. Ther have been a lot excellent books very recently on the suject. I mentioned Christopher Browning. There is also Michael Burleigh, Richard J. Evans, Victor Klemperer, Adam Tooze and Mark Mazower. All of them address this point from different angles. Gives one a good overview of what was known and not known. The fact that there was a Wannsee Conference for instance was not public knowledge, the train loads of prisoners going east to destruction as a result of the Wannsee Conference was common knowledge. It was also to impossible to prevent the soldiers who went home on leave to shut up about what they saw at the fronts. Many wartime diaries have been recently been published that demonstrate this exactly.