For context I have audhd. I’ve always been confused about the association between stacking toys and autism. I don’t particularly remember stacking toys as a kid other than of course I did because I was a kid. Don’t lots of kids try to stack stuff as high as possible occasionally? Why is this seen as an autistic trait? Is it a stereotype due to the historical bias towards autistic boys with a particular presentation or something else? If it really is associated with autism and not a bias, why do autistic kids do it more?
They are more likely to be concerned about sorting them according to criteria that matter a lot to them but not for any practical reason, organizing them spatially like they’re a library of books that need to be kept straight, stuff like that. Making neat stacks can be very appealing to some people.
You’re not going to find answers to why autistic people do autistic things.