It is entirely believable that a person with substantial trace on HN and ties in the field would rather create a throwaway than post such remark under his main account.
Then they would not out their identity by claiming to have worked with the author. That piece of information alone whittles their identity down to maybe 100 people. Out of 100 adjacent academics how many post on HN, with this style, and this specific level of knowledge in that specific subfield? They may as well have just made the account their irl name. Anonymity is not a realistic goal. Assuming a realistic poster means it's reasonable to suspect their earnestness.
You are frustrated and this makes you act in a deliberately obtuse manner.
There is a world of difference between "anyone who has worked with the guy" and "has worked with the guy + has hundreds of comments on HN identifying career track over the last few years". The former grants each suspect plausible deniability, while the latter pinpoints the true author.
> Anonymity is not a realistic goal.
It obviously is for a throwaway account. Time to reread the classic