One caveat here is that the author of the article posted it here in HN for comments -- it's not that someone else did, and this is unfair because HN was never supposed to take a look, etc. They expected a review, otherwise they wouldn't have posted it here.
HN is not an audience of laypeople (mostly) and will critique the article with a different mindset than a novice that might be impressed by the visuals (which are impressive).
So I think the reaction is both to be expected and reasonable: HN will critique how correct the explanation is, and point out the mistakes. And there were a couple of fundamental mistakes due to the author not being a subject matter expert.
HN is not an audience of laypeople (mostly) and will critique the article with a different mindset than a novice that might be impressed by the visuals (which are impressive).
So I think the reaction is both to be expected and reasonable: HN will critique how correct the explanation is, and point out the mistakes. And there were a couple of fundamental mistakes due to the author not being a subject matter expert.