This is my big question. The guy is legitimately nuts, no doubt about that. And to cover it up all UCLA has to do is act like his break from reality happened as late as possible. Nothing he says will be taken seriously because it will be all be the ravings of a madman.
But what I want to know is when it actually started. He clearly had problems before then, from what the students are saying, so at least a year longer than they will be willing to admit. But I want to know how long he was suffering delusions, being threatening towards blonde women, showing a severe disturbance in his mental faculties, but it was excused due to being the black man in the philosophy department. It's easy to say he was like this the whole time, but I doubt that. But I do think he lost contact with reality some time ago but wokeness kept UCLA from doing anything about it, and it would be very interesting, if difficult, to try and pinpoint just how long they let the writer of this manifesto, with all these thoughts bouncing around his head, stay a part of the university.
He hadn't talked to his mother for five years, and she didn't read the emails he sent her until she was told there were likely violent threats in there - is that a potential line to work from? Before he finished his PhD? After, when he saw what little reward that gave him? Before he started stalking - or was that a baseline level of crazy he always was and he only became manifesto-crazy after?
Basically, as has been pointed out, 800 pages doesn't appear overnight, even on a manic spree. So I'm treating it as a rule of thumb that the longer his craziness was allowed to go unchecked, the more of his opinions in his manifesto were considered acceptable for him to have while he was lecturing at UCLA. Either that, or they were too afraid to do anything about him because of how it would look, which is about as bad.