The term "neurotypical" did NOT originate the way you claim. It was coined on the old SJU Autism list, during the "Snore Wars" in the aftermath of the 1993 conference where "Don't Mourn For Us" was presented. It was coined to do exactly what Alyssa said: " I think we need a word for "close enough to the alleged norm to get privilege from it."
Therefore it is clear to me that the term is older than I had believed by some five years, and did not originate as a joke, because Jim Sinclair is someone who would have authoritative and trustworthy information on this topic.
I should here also clarify that my essay was an argument for the idea that we should move on from this term because of the reasons I specified, and not an attempt to claim that everyone agrees with me. Many do, but many do not.
My primary reasons are that the term is often used disparagingly, and that it is easily used by accident against people who are not, in fact, accurately described by it. An important thing I think about this second issue is that many of those who fall under categories known as "mental illness" and "intellectual disability" may be less privileged in some ways as a group, right now, because of political gains we have made since the coining of the term, than are Autistics, and we can do some good here instead of doing harm.
I regret my historical provenance error and thank the ones who had better facts for coming forward.
In other news, I still agree with myself about the idea that we should recognize gains we have made and behave inclusively toward those with all forms of neurodivergence, including those with greater stigma, and that calling people "NTs" does not help us do this. I also reiterate that while I agree with myself and those who agree with me also agree with me, it is manifest that other people do not.
Thank you for listening.