That's not what anyone is saying. There are many classes of human (and non-human) condition where it's best to allow a subject-matter expert to diagnose, and where armchair diagnosticians can do a lot of harm. This is one of them.
The idea that you can "diagnose" someone with a mental illness based on reading their court filings and things they've written online, without ever speaking to them in person, is... well, just bonkers. It's irresponsible, at best.
Someone can exhibit anti-social behaviors without having a mental illness.
This is as frustrating as people I know who are constantly saying "I think so-and-so is autistic/has ADHD". Yes, sometimes it's correct, but often it's not, and the outward symptoms of those two conditions often lead to a true diagnosis of something else entirely.