Why is my son so racist to people with Down Syndrome?

Your son sounds like a psychopathic bomb waiting to explode. His behavior just screams red-flag, potential/future murderer. I know those words may be harsh and not what you want to hear, but I'm not going to tell you "what you want to hear". He is very psychologically disturbed, his Asperger's may be the cause and needs help. It could be he hates the way persons with Down's Syndrome look: "slanted" eyes, agape mouthed, tongue protrusive (depending), etc. Before things got P.C. , the term was "mongoloid". He can't be "racist", per se, towards people of this disability as they all have the same characteristics/features, regardless of race. He probably hates them or any disabled person because he sees them as weak and inferior, and needs someone/thing to act his rage upon. Have you ever wondered about the causes of this rage/anger he has? He, himself, may suffer from a "mental retardation" why he goes into fits of rage and aggression. Please get him examined (pray you have insurance), tested, whatever, because as he grows older he just might do something to break your heart, destroy your family, and someone else's...