Because our sins of prejudice have been paid for, God calls us to judge correctly.
In the movie "Shallow Hal" Hal, played by Jack Black, sees people based on their outward beauty. He is then hypnotized by the self-help guru, Tony Robbins. For the rest of the movie, he sees the people around him based on their inner beauty.
In a way, that's what the Holy Spirit does for us. Our values and our view of the world is transformed by His power.