I have ADHD and it's incapacitating, I literally can't think straight, have no sense of time or organisational skills, and can't live independently. I also have autism and noticed the same thing as you, that it's self-diagnosed, exceptionally-high functioning people (or literally just not even autistic) who perpetuate silly stereotypes as if autism is just a funny quirk rather than a disability. They make a great big fuss about the most minor and most palatable symptoms of autism, like mild stimming and mild sensory issues. They are also the ones most likely to boast about how autism is a strength, not a disability. I have struggled to get support because of the stereotype that autistic people must have talents, genius, or special skills. Unfortunately, most of us don't, including me.
I don't believe that she was diagnosed. I seem to remember her tweeting about how she can't produce her evidence, as if having diagnosis reports lying around is the most ridiculous thing ever. I have all my diagnosis assessment/reports in a file, as I regularly need them for proof for things I'm entitled to.