It is a form of fear of losing that popularity, even though Pilate had the power to set Jesus free, he did not, because of the crowd. I believe it is the mind of the person, seeing wrong as wrong and right as right, no matter the circumstance. However, the prophecy had to be fulfil, and Pilote had to please the crowd. The answer is "fear" of losing that high, it is one of the enemy's ploys to sink you deeper into sin.