KB8CWB wrote:
I believe much of this is due to instinct. If you look at much of the animal world, it is the same. Those that are perceived as different or defective are either killed or driven out of most social animal groups. Humans are no different. We like to think being human we would be civilized, however instinct drives the defectives out for the survival of the group. Both to keep the gene pool healthy, and if in the case of predators it does little good if the one defective can't read the social cues of the rest of the group. This behaviour in the wild can put the whole group at risk. Yes in some instances it is intentional for humans to do this. Even if they are good and compassionate people it can be a subconscious thing for most. Kids haven't learned socially acceptable behaviour so when young will let instinct take over. And once they do even then they will just ignore us and not include us in on their activities. Just my observations and conclusions fwiw...

I'm not normally one for quotes, however I feel as though this suits the crux of your statement well.
?What would happen if the autism gene was eliminated from the gene pool?
You would have a bunch of people standing around in a cave, chatting and socializing and not getting anything done.?
-Temple Grandin