In regards to "softening", eg:
>"Hey, you got your math on example X wrong... I think it actually works to 11.7. Anyways, I only recognize that because I made that mistake dozens of times myself, it's a common one to make, just wanted to point it out."
Stuff like that always reads as condescending to me. Not just a waste of time, but an expense of time which actually hurts ones cause. I suspect my feelings are neither unique nor universal, and that delivering respectful and constructive criticism involves knowing your audience. So it's always going to be difficult if you try to do so to a stranger.
> delivering respectful and constructive criticism involves knowing your audience.
I do not take offense, because I know the commenter means well and is erring on the side of kindness, but personally I'd rather see "s/wizen/wisen/". It communicates no offense (by being low-effort on the part of the commenter), and respects both my ability to research on my own why I made this particular mistake, and my own motivation to correct the mistake.
Stick to the facts.
On the one hand, there are people who would be offended by a reply of “s/wizen/wisen” _because_ they feel it’s low-effort, nitpicking, and/or talking over their heads (not everyone would even understand that comment, even on HN).
On the other hand, there’s many people like yourself and many commenters on the original article who feel that “padded” criticism is condescending.
The dilemma is that both the “Stick to the facts” group and the group who feels that “just the facts” is rude — feel strongly that they are right and everyone else should know that.
At least you’re willing to assess the intentions of the speaker rather than attacking. Unfortunately, not everyone will do that.
Perhaps the real takeaway is: there are no hard and fast rules when it comes to interacting with people.
I think there is one, actually, which is: be consistent. At least then, those who interact with you regularly can learn your style and calibrate accordingly. Even on forums, you can look to one's commenting history to calibrate your reading of a comment with no other context. I've certainly done this, on occasions when some comment deviated significantly from the norm of polite discourse, usually to find that the commenter simply has a different norm than I expect.