As another person who thinks that the Sequences and FAI are nonsense (more accurately, the novel elements in the Sequences are nonsense; most of them are not novel), I have my own theory: LW is working by accidentally being counterproductive. You have people with questionable beliefs, who think that any rational person would just have to believe them. So they try to get everyone to become rational, thinking it would increase belief in those things. Unfortunately for them, when they try this, they succeed too well--people listen to them and actually become more rational, and actually becoming rational doesn't lead to belief in those things at all. Sometimes it even provides more reasons to oppose those things--I hadn't heard of Pascal's Mugging before I came here, and it certainly wasn't intended to be used as an argument against cryonics or AI risk, but it's pretty useful for that purpose anyway.