It is functional for leaders to be more reluctant than most to "take sides" in common disputes. Our leaders do this, and so one can in fact signal high status by being "above" common disputes. Our leaders are in fact wiser than the average person, and in addition we want to say they are even wiser, so it makes sense to call people who signal high status as "wise." Furthermore, on average across human disputes with near equal support on the two sides the middle position is in fact the more correct position. So in this sense it does in fact signal wisdom to take a middle position.