This is an interesting debate. I found this article as I was able to experience a relationship followed by great difficulties with a girl who had a highly autistic brother. What caused difficulties and huge problems was the mother of this girl's efforts to isolate her child. Of course the mother was not intentionally abusive but would isolate her daughter from relationships with others and the world under the guise of protecting her. I once watched a documentary with the mother of an autistic child telling the child not to play with toilets in the bathroom. Of course she made logical sense, wanting her child not to play in room which could be dirty but her protection of her child, in fact isolated her child from the world around them. I saw the mother of the girl create perceived threats which then led her daughter to isolate herself. This was usually people.
So I question whether or not these children are really intelligent or have they been forced by their parents not to play as their parents have directed them to focus on other 'higher' things which leads the child to become isolated. Rather than engage with and interact with the world the parent tries to be the childs guide, forcing the child to resist what the parent may see as fickle. The child enters their own world.