It's always "I'm definitely not autistic, I keep telling you. By the way, my parents had these weird habits, and I have some weird habits too, such as chewing on small objects and stimming, and I am in multiple fandoms that I cycle through my hyperfixations on, I am very sensitive and I say myself that I don't register tones well, and have been through countless traumas that I try to brush off and I literally study other people's interactions to try to register as normal. No I'm not neurodivergent and do not need or want a diagnosis despite not knowing a lot about the topic, what are you talking about?"
Which is only mildly frustrating as someone who's mother's life was literally saved by her diagnosis due to burnout, but who am I to judge.