So this guy had years to plan this and managed to kill three innocent people? Doesn't seem all that intelligent and well thought out to me.
Also, people get fired. Guy clearly has a distorted view of himself. He really thinks he is doing something grand an important by killing people and threatening others. If he really wanted to expose these people he could have gone about in a much better way that could actually have led to him being respected. Instead, the manifesto and the whole thing do nothing but justify his being fired.