There is a skill not taught in schools that I might describe as “how to conduct code reviews” and it applies in industry as well as HN comments.
A reason to be afraid to submit may be that the number of respondents that don’t know how to review may exceed the number that do, causing the net result to be more destructive than constructive. Which brings me to another skill — how to ignore input that (even if you receive it) does not really matter, or at least not right away or not as much as other things.
If only as a profession we could resist the urge to quibble about things that probably are fine (or at least not pressing) so that there is more time to dig into the heart of a design or implementation. Yes, that’s an interesting algorithm; no, let’s not segue into the choice of back-end on the web site that happens to host the documentation; yes, that will help with maintainability; no, the number of spaces here does not really matter; yes, that is a good recommendation but not under these time constraints; no, I will not rename 125 variables to suit your arbitrary choice instead of my arbitrary choice.
I would also add that “review” is often misinterpreted as “pure criticism” (again, in code or in HN comments) and it can be nice for unsolicited positive feedback to occur too. Things like “I like how this was done”, or “I’ve never seen anything like that, clever” as opposed to an unending wake of negativity that tries to tear apart any given project.