Why do you think the tragedy of the Wilhelm Gustloff is so relatively unknown? Certainly, other ocean liners that sunk during wartime have received a great deal of recognition (ex: RMS Lusitania), so why is this story only known to a relatively small group of people interested in World War II?
Thanks for your question about why the tragedy of the Gustloff is relatively unknown. I think there are a few contributing factors:
When the ship sank, the Nazis tried to conceal the story (and the fact that they were losing the war.) The Soviet submarine commander who torpedoed the Gustloff was dishonorably discharged shortly after so perhaps the Russians weren’t drawing attention to the story. And after the war, Germans didn’t publicize the sinking as they felt it was inappropriate to speak of their losses during the war considering the atrocities committed by the Nazis.