I think it’s a combination of guilt, shame, helplessness, and an inability to connect with their autistic children that makes them hate it so much.

Guilt because autism is partially genetic and they blame themselves (of course, many genuinely stupid/brainwashed people think they caused it with vaccines). Shame because they’re too close minded to be proud of children who aren’t like them. Helplessness because there’s no cure for it and the symptoms can be incredibly severe. The inability to connect could be due to the severity of their child’s symptoms, but it’s more likely because their child doesn’t respond the way they expect and they and their child don’t recognize each other’s emotions from their body language.

All of that is made even more difficult if they themselves are on the autism spectrum and reject that.

I’m autistic and I come from a family of high functioning autistic people. My dad doesn’t think any of us are autistic, even though it’s very clear (he and I used to bond over our mutual love of excel and he has always been uncharacteristically thoughtful about my absolute intolerance for the sound of knife sharpening). I think part of the block for him is accepting that his own family history of ham radio operators, train engineers, and cryptographers might not be totally neurotypical.

He has accepted his ADHD, but it’s a hard diagnosis to disagree with when you’ve literally had over 60 jobs. Another barrier is that he feels like it’s “too many things” to have more than one mental health diagnosis, even though he is aware of the existence of comorbidities. Because he thinks he’s normal, he thinks everyone struggles with social cues, overstimulation, and changes in routine. Even though he knows he has ADHD, he got a master’s degree and had a successful career (despite changing jobs a lot), so he feels like people who struggle with ADHD are weak or lazy.

It’s fucked up, but it’s also a predictable reaction to growing up in the environment he did. Luckily, none of his kids takes his opinion on this to heart, and he was always good and reasonable enough to help us seek treatment for our mental health. My siblings are raising their neurodivergent children with much more acceptance and support than what we got as kids, just as he raised us with more than he got. Hopefully my family is not alone.