Why could the Jews not understand Jesus washing the disciples' feet?

Les explains that this is what threw such a curve at the Jews. They were looking for someone to come in on a white steed, like a Roman general or Roman emperor, but He came as a servant. He epitomized that when He washed the disciples’ feet. They could not understand how the very Creator of the universe, who had come to be king not only of Israel but of the whole planet, could get down on His knees and wash the disciples’ feet. In contrast to Adam, who was given dominion, Christ in His earthly ministry came not as the royal king as yet; He presented Himself as king but came more as a lowly servant, riding upon the foal of the ass.