They are wrong. I worked at an institution for the retarded, and one of our patients was autistic from an Amish family...
And autism was widespread in the 1950's, but those kids were labled "retarded". Now any retarded kid with behavior problems is called "autistic", which is more pc....
Autism has a strict criteria, and can actually be caused by measles, mumps and other viruses that cause encephalitis...what is different now is that pediatricians who trained after 1980 have never seen a case of measles encephalitis...
To follow up on Ladydoc's observations... as a special education teacher in my little corner of Virginia, I have seen this very thing happen. There are kids that are indeed autistic and these are the ones that are identified early on --around 18 months to 3 years. I do not work with early ed, so I will leave comment on that to others who do. But in upper elementary school and middle school I have seen about 20 times or so kids who are low to very low functioning, but not so low they are mentally retarded. These kids hav behaviors that range from bizarre to quirky to just flat, depending on the kid. They do not perform well in school, so eventually they come up to a special education referral. When we look at their WISC and WIAT scores nothing pops up as learning disabled but a savvy parent will hone in on the fact that the child's behavior does not mimic those around them. That opens the door to an educational autistic label--not medical--educational. The child then receives communication services or accommodations as a child with autism.
I've also seen this happen when the child shows signs of an emotional disturbance. It is easier for parents to accept an autistic diagnosis rather than emotional disturbance.
I dont have a comment over whether or not this is "right" or not. Many times the parents are desparate for help and this is the way to go. But in my opinion kids that are diagnosed autistic older present different needs than those diagnosed younger. And I think the younger a child is diagnosed with autism the more likely it is a true medical diagnosis, not a educational one.