You underestimate the number of NoNos aboard that demand bland. No salt, no pepper, no garlic, no onions, no peppers , no oregano, no basil, no herbs or green things at all, no spices, NoNo!
Just go ashore any where in Japan and have the miso soup. Then have it aboard ship. Miso has flavor, why not on the ship? NoNos demand bland.
What great steak house have you been to that prepares your main course with zero seasoning, just a cooked piece of meat?