Huh, I’m gonna have to think about this one. My experience growing up was that, despite being neurodivergent, I never felt like I was being called it anymore than anyone else, and that was probably at the height of its informal use (when it was considered just another way of calling someone stupid).
However, it does make me wonder if the declaration of it being a slur backfired. Is it used as a slur against neurodivergent people more often now than it used to be? I’m wondering if the people who were using it as a generic insult stopped using it, which meant the people using it as a slur became the only users, which solidified its status as a slur.