There are not so many reasons. Friar Sand is not only called Friar Sand, but also called Friar Sand. It is impolite for Pig Bajie to call a pig directly. The Monkey King is arrogant. He introduced himself as a monk, but he was only called the Monkey King.
Who dares to go against his wishes? Tang's monk is really a holy monk, so it's not qualified to call him a monk.