Being the kind of writer I am, whenever this comes up I am tempted to suggest ways it could have been done better.

The premise kind of does work in a setting like Harry Potter, the wizarding world is insular enough that a clever kid could bring in some new ideas. The problem is Eliezer wanted to throw in too many shortcuts. Its not enough for creativity with transmutations to give the protagonist a small edge, transmutation is made into the ultimate all-purpose spell so the protagonist can exploit it easier. The protagonist isn't just moderately better at Patronus with some muggle psychology, his patronus can kill dementors. And the philosopher's stone is changed into some ancient atlantean super-magic, because fuck wizards ever inventing anything, and also instead of some moderate rate of its typical mythological powers it is super transmutation.

But, first, I am not glazing the work of Rowling, even indirectly, no way, no how.

Rowling went mask off transphobe in 2018, HPMOR finished in 2015. So I won't blame Eliezer for not picking a different fandom at the time. Eliezer has actually said moderately supportive comments, including of using people's preferred pronouns (we've mocked another lesswronger for writing long screeds complaining about this). In general, I think the average lesswrong attitude towards trans people is better than the average American's attitude... but that is because the bar is in hell. But yeah I've seen plenty of shitty takes towards trans people on lesswrong.

Second, HPMoR was cult shit all along, not meant to teach science but to sow distrust of scientists under the glossy sheen of being able to name the six quarks.

Yep. And it didn't even stick to its premise of "try to do science to magic and compare muggle scientifically gained knowledge to magic" and instead went into some Ender's game pastiche followed by Death Note style "I know you know I know" plotting, then Harry gets handed all the magical power handed to him at the end of the story thanks to Dumbledore following some insane combination of prophecy.