I enjoyed watching that, even as someone who really liked HPMoR.

I wasn't aware of a lot of the wider context around the author and the rationalist movement. For example, I read HPMoR with Harry calling all the wizards in the book NPCs as commentary about Rowling's writing (that her characters and magic system bend to suit the plot, as very few characters have any agency) so every other person at Hogwarts is an NPC, but if Yudkowsky actually believes that people who aren't rational are, effectively, subhuman, then that twists the interpretation of HPMoR rather dramatically. I'm still not convinced Yudkowsky thinks that, but it's disheartening to hear that some HPMoR readers basically founded a cult that does believe that.

Thanks for the link! I should check out his other videos. He seems like a really hoopy frood.