Eliezer complements Musk on the creation of community notes. (A project which predates the takeover of twitter by a couple of years (see the join date: https://twitter.com/CommunityNotes )).
In reaction Musk admits he never read HPMOR and he suggests a watered down Turing test involving HPMOR.
Eliezer invents HPMOR wireheads in reaction to this.
It was a hype at the time, but given the size of the target audience, it's not surprising that quite a lot of people found the universe engaging enough to generate a vibrant fandom (which I believe is mostly comprised of adults).
In fact I believe a big drag on HP as a franchise is that "kids today" see it as something their parents like.