I feel you've made an argument towards me with your comment, and it was welcome because you posed it rationally and without making it personal. It's impossible to pose a fight with a stranger rationally and impersonally, so I'm not sure that that analogy is a good fit.
I think the distinction is that while it is productive for you, it may be the opposite for your interlocutor. People have conversations for different reasons, and the reasons you have are a strict subset of those. And in real life - outside of academia and some of the tech world - their reasons rarely align with yours.
(Lesson learned the hard way).
If you're addressing the physical fighting analogy, yes - it is an imperfect one. It is also not the main thrust of my argument.
If you're referring to the wider point, I don't see the relevance. It's not a given that the purpose of commenting on HN is for sharpening writing skills and rhetoric. It no doubt is the purpose of some on HN, but not everyone.
To take the statement to a pointless extreme, you can also choose not to reply to someone who is openly insulting you on HN. That doesn't make it OK to do so.
> I think that there are positive perspectives you could take on some of these bullet points
Arguing with someone on the Internet is positive only if the other party also wishes to argue.
Kind of like going out to the street and physically fighting with a random person. It'll definitely sharpen your fighting skills, but it's not a positive if the random stranger doesn't want to fight.