Why Do We Teach Kids to Hate?

I have about 21 kids in my class. Some white, black, Hispanic, Asian, and Indian (not Native American but from the Middle East). Anyway, I've heard some of my students make comments that demeans a person because of their skin color, origin, size, intelligence, designer label and more. I like to think that as a teacher, I can teach tolerance. I want them to treat all people kindly. I know you can't be best friends with everyone, but try to get to know a person based on qualities that can't be seen. So, I always tend to make my seating chart in a way that you are bound to sit next to someone different. You may sit next to someone that is of a different gender, language, neighborhood, etc. I encourage them to work in groups that require team building skills. When describing each other, we use words that are positive. So, if I average 20 kids per year, I like to think that I have opened the minds of at least 200 individuals so that we can have a less hateful world.