Careful. Yudkowski and LW have a dark side. (google Roko's Basilisk) Rationality applied to ethics is a sticky wicket. You have to subscribe to some metric of "good" in order to weigh and compare outcomes. EY's definition of good is ruthlessly utilitarian, and that has some extreme, nay dire consequences for certain thought experiments. Consume this philosophy at your own risk.
The Roko's Basilisk thing is way overblown. The author addressed the issue here: https://www.reddit.com/r/xkcd/comments/2myg86/xkcd_1450_aibo... And of course some of the topics he writes about are always going to be controversial. But utilitarianism is hardly radical.
I don't understand what Yudkwosky's trying to argue there. "Even though I don't actually believe in it, I yelled at him for invoking the wrath of the nonexistent basilisk that I don't believe in"?