Because a world where every one believes the same thing and does the same thing would be boring and stagnant. Eventually, if we all thought and acted the same, we would die. It's differences in personal views that spur us to learn and grow. Unfortunately, there may always be those who hate on the basis of the differences between people. But often that hatred is based on fear and ignorance, so we work to educate in the hopes that knowledge will lessen the fear. That doesn't mean we sacrifice the things that make us different, like religion or race or political affiliation. We learn tolerance and patience and communication skills and most importantly, we stand up for each other when they are faced with racism and discrimination.