why would survival have been an embarrasment?
The Yamato was built at great cost during the height of the War. Previous to its single engagement it had a reputation as a floating hotel for Imperial Navy brass. The Army, fliers and common Japanese had suffered terribly because of a War that the Navy was preceived to have started. By the time the Yamato set sail no one expected it to come back, few expected to even score against the Americans, and in the event it did not. Its demise probably provided US Navy fliers invaluable target practice. Japan would have been better served if it had been scuttled.