What you are trying to engage with here is a very unhappy and quite possibly psychiatrically ill person, who happens to have an above-average level of intelligence. Such persons abound. In an actual community of real people with real, face-to-face interactions, these people are brought up fairly sharply for their antisocial behavior, and they either learn to behave more politely or they are shunned. In the context of this forum, the individual is able to spew his vitriol all over the place without negative consequence to himself, so there is no hope of ending his foul behavior.
Nailed it, not surprisingly. If you read back through his posts, he repeatedly accuses others of being "mentally sick." So, there's projection too.
