By 'rape cult' I assume you're referring to the zizians? https://en.wikipedia.org/wiki/Zizians - the internet is convinced Yudkowsky has nothing to do with them, so it's pretty disingenuous of you to claim otherwise without citing sources.
There have been plenty of allegations about the rationalist community beyond the Zizians, who really don't even qualify as a sex cult as far as I know? Violent, obviously, but they seem... ideologically asexual?