The last paragraph really drives home that this person just led a fucked up and depressing existence, and then, on top of that, a close friend dying/being murdered/suiciding in a clearly confusing arrangement.
I dunno. I don't feel overly angry at this person, what they've done is utterly and truly awful and should never have been done. But I can see how an awful life like that could totally warp your view of the world. I'm extremely mad at our shit society that frequently lets people get to this point without helping them or really giving a shit.