The author's entire point, and the entire point of phrases like "nothing about us without us" is to get neurotypical people to stop talking on behalf of autistic people and to give them their own voices.
I think the author spends a lot of time pointing out that everyone in the autistic community is unique, and I think they spend a lot of time pointing out that even areas where there is broad consensus like identity-first language will still have some detractors among the community. I am unsure what else they could possibly do to make it more clear that the autistic community is not a monolith. They literally have a section titled "Key Takeaway: We Are Not a Monolith".
It feels like a really uncharitable/shallow reading to me to say that the author is pretending to represent anyone when they spend so much of their time going out of their way to specifically avoid causing that perception.
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> Also i have a distaste of the author listing their "disabilities" in their twitter bio.
Come on, people list far more trivial stuff in their Twitter bios than this. Sometimes it's nice to be able to find other people who are like you online, and self-labeling can help with that.
People being comfortable enough to talk about aspects of their identity in public is not something that's worth being mad about. And autism is 100% an aspect of people's identity, it's a really wild claim to say that a condition that affects people's brains basically from birth and for the entirety of their lives wouldn't be a part of their identity; your brain is a big part of what makes you you.