Pahahaha that's hilarious. Let me give a quote to give this some context: "People like us, graduates of the merchant-marine school, were shipped off to the most forward positions while those bastards from the Imperial naval academy sat around on their asses in the Yamato and Musashi hotels."
The moniker partly derived from how little the Yamatos sortied compared to other IJN ships, and (at least in this case) how much Etajima graduates were loathed by other servicemen. Oh wait, they explain it on wikipedia. Meh, I already typed it, so you get to read it.
Source is "Japan at War" edited by Haruko T. Cook and Theodore F. Cook. New York: The New Press, 1992, page 301.