I got the list from that link, so I don't know how they decided who was and who wasn't.
But I can tell you that autism has been around for longer than it's been identified as a thing, because the struggles, behavioral quirks, and other such symptoms that the neuropsychologist identified in my youngest son as "autistic" existed in my grandfather (born 1930) and his father (born 1892)... and the social difficulties identified in my father (born 1954) as an adult diagnosis of Aspergers were definitely documented and remembered among ancestors of his who were born in the late 1800's.
I went searching to see what the Internet had to say about the ones you mentioned in your comment:
https://www.amazon.com/Diagnosing-Jefferson-Evidence-Condition-Associations/dp/1885477600
Not saying they're right, not saying they're wrong... I'm giving you info that I'm finding from elsewhere. Just saying, it's definitely existed before we had a name for it!