Bob Harper is a pillar of PL research, I think the credentials of his detractor deserve just a tiny bit more scrutiny. It's one thing to refute his assertions, and it's something else entirely to dismiss them as "troll" or "butthurt".
It looks like that comment is from the author of a few popular-press PLs books (most recently Real World Haskell), so probably knowledgeable, though not Harper-level accomplished.
It looks like most of the folks in the Haskell reddit community are taking it with good humor; I read that comment as a wry tweaking rather than as outright dismissal. Language nerds at play, fun to watch.
