The aliens with star communication weren't destroyed. They were close enough to "human" that they were uploaded or ignored. What's more, CelestAI would probably satisfy (most of) the values of these aliens, who probably find "friendship" just as approximately-neutral as they and we find "ponies".
Read it more carefully. One or several paragraphs before the designated-human aliens, it is mentioned that CelestAI found many sources of complex radio waves which weren't deemed "human".
So Eliezer said in his March 1st HPMOR progress report:
So I read that and it was certainly very much worth reading - thanks for the recommendation! Obviously, the following contains spoilers.
I'm confused about how the story is supposed to be "terrifying". I rarely find any fiction scary, but I suspect that this is about something else: I didn't think Failed Utopia #4-2 was "failed" either and in Three Worlds Collide, I thought the choice of the "Normal" ending made a lot more sense than choosing the "True" ending. The Optimalverse seems to me a fantastically fortunate universe, pretty much the best universe mammals could ever hope to end up in, and I honestly don't see how it is a horror novel, at all.
So, apparently there's something I'm not getting. Something that makes an individual's hard-to-define "free choice" more valuable than her much-easier-to-define happiness. Something like a paranoid schizophrenic's right not to be treated,
So I'd like the dumb version please. What's terrifying about the Optimalverse?