I think it likely that autism and ADHD are far more prevalent than is currently realised.
Our world is designed for neurotypical people. The way schooling and work are designed is a struggle for ND people.
As is social life. Many ND people find friendships and relationships difficult to navigate and their approach and behaviours may not match others'.
Many issues may well stem from neurodivergence, whether recognised or not.
Only very recently, experts were confidently asserting that autism & ADHD only affected boys. = 51% of the planet ignored, and a huge cohort of women and girls undiagnosed and unsupported. So many only being recognised later in life.
Partly because the world isn't designed for them, it's likely a large sector of the prison population is ND. If everyone going into youth custody and prison were effectively assessed I'm convinced many more would be identified, which is a first step to understanding and supporting.
It gets criticised here but yes I do think we should be open to the possibility that behaviour issues may - MAY - have neurodivergence at their core and it's wise to consider the possibility. To keep an open mind.
Because ND people can be helped and supported to understand and live in a world that is overwhelming.
And NT people can be helped and supported to understand their parent, partner, friend, colleague, child, pupil etc may struggle to achieve that, and have greater insight into WHY things are happening.
If neurodivergence can be ruled out, then whatever's left is their personality, upbringing, education, life experience and sometimes conscious choice of behaviour in play. Then you can decide if you are prepared to accept that. Or do something about it.
So yes, though it can cause a knee jerk reaction in many people, like OP, I think raising the question, having the conversation and keeping an open mind about the possibility are valuable.
And it's possible to be ND and nasty - or ND and lovely.