Good points.
JMO-- more musings on his behavior, self preservation, garnering empathy, apparent motivation...
Any chance this could be some habitual splitting behaviors? Maybe he had some symptoms of borderline personality disorder?
Might what we have observed be a little window into what it was like to know him, work with him, have a relationship with him?
I think his whining essay, along with his (alleged) murder pattern add up to someone who's looking for sympathy and knows how to obtain it, even as he (allegedly) is killing in cold blood.
He seems skilled at leaving lots of turmoil in his wake, alive or dead.
I agree. The manifesto was just a ploy for sympathy after having already killed and knowing he could continue to kill and get rid of life long anger, resentment, frustration, inadequacy while on his way to suicide. That rambling mess made it clear to me that this was lifelong. While his issues may not have been the in your face kind upon first meeting, I'm sure they were after getting to know him and listening for a while.
I did not understand speaking to people he never knew, like Hillary Clinton, but hey, he'd just murdered, was going to murder some more, and he was about to kill himself so....