It's not a joke. It's literally someone on the verge of a psychotic break from reading too many LessWrong blogposts. Those folks aren't only into game-theoretic polyamory and shitty harry potter fanfiction, far from it.
Just because it isn't a joke doesn't mean it isn't hilarious though. Look into roko's basilisk, if you dare!
Still cracks me up, that page.
(BTW you should definitely read Permulation City, and the 'sequel' Diaspora. Try not to found any cults tho.)