Most people just go along to get along, because they fear losing their position. And they should fear it, because it happens a lot. Supervisors are people, and many people are emotional and hold grudges, even when it is not in their best interest.
At the end of the day, I have accepted that some supervisors just won’t acknowledge they’re wrong–so I focus on what I can control and try not to burn myself out fighting a wall.
Picking battles is a must, otherwise it really is a never-ending battle.