Teaching Children?

I was working at a school with a child, we will call him Grant, with disabilities and in working with this child I have come to realize that frankly children are cruel.    Most of the mainstream children do not like being with Grant.   In fact if he sits down at a table the children already sitting there will get up and move.  For the most part many kids dont want anything to do with him.    No one has taught these children that sometimes kids are different and you shouldnt treat them any differently because of that.   The children do not understand that all people have feelings and all people need to be considered.    Grant is in the after school program to get more social experience with children but do to the children's reaction to Grant he spends an awful lot of time a lone.   I find this very disturbing.   It hurts me to realize that the values children seem to be picking up on are values of being the same.   Children are taught to shun people who are different, not to look at every body's strengths to figure out what these children could do to enrich their lives.   Every one can teach a message but you have to pay attention to the little things that might not be expected.