The perceived explosion of autism is not solely the result of more extensive knowledge.

Absolutely true. Its also the product of desperation and wishful thinking.

It is completely understandable that parents would wish to find an explanation - however fanciful - for a merciful providence having inflicted this horror upon their children.

Be that as it may, there is as much (if not more!) evidence that the condition is the result of children being abducted and experimented upon by space aliens as there is that it is caused by environmental factors or vaccination, etc.