Globally 0.29% of people suffer from schizophrenia (lifetime risk of 1%) so it shouldn't have been surprising Usenet (or, really, any forum system without moderation or some similar kind of control) would experience their presence.
Why wasn't Henry Spencer listed as a Usenet personality (the good kind)?
https://www.who.int/news-room/fact-sheets/detail/schizophren...
Schizophrenia affects approximately 23 million people or 1 in 345 people (0.29%) worldwide.
That's a lot of people.