It is most certainly not true that the majority of prisoners are "neurodiverse".
It is true that you can google to find evidence that the majority of prisoners are something, anything, anything at all
You can google to prove the majority of prisoners are dyslexic, you can google to prove the majority or prisoners are victims of child abuse, you can google to prove the majority of prisoners are convicted because of cannabis, or you can google to prove the majority of prisoners are psychopaths.
What is true is that the majority of prisoners are disadvantaged in some way, but it is absolutely not true at all that the majority are neurodiverse.
I teach in prison, and and levels of ADHD are lower in a prison classroom than in a comprehensive classroom, largely because prisoners are older, and many of the behaviours and symptoms associated with ADHD disappear with age.
If someone with ASD chooses to break the law they go to prison same as anyone else - you might say they are more likely to choose to, but it is still a choice.
I would say I see a lot of injustice in prison, in that neglected children not taught right from wrong, children not encouraged to do well in school, children from families where parents are abusing alcohol and drugs, many many of our young people are born into situations where prison is a far more likely outcome for them from the day they enter the world.
"neurodiversity" is not a factor in that in itself, beyond the fact that the word can and is stretched to cover behaviour problems linked to trauma and neglect