Why was this downvoted?
edit: grammar
Yes, because it breaks the HN guidelines:
Resist commenting about being downvoted. It never does any good, and it makes boring reading.
Everyone commenting here needs to absorb this rule and develop the small amount of discipline it takes to just not do it. Optimize for signal/noise ratio, because that's what serves intellectual curiosity (https://news.ycombinator.com/newsguidelines.html).
Personally, I've felt a great uncertainty whether downvotes are intended to be used for "I disagree with you" or "your comment isn't what we accept here at HN". I've always assumed the latter but think I heard something from you/PG indicating the former recently. There isn't anything about it in the guidelines. I don't expect a reply from you here (not sure it would do much good, other than just for me) but if you ask around and others have the same lack of clarity, it might be worth writing on.
Lastly, thanks a lot for all the great work you've done for HN in the past several months! (longer?)
There has never been a rule against downvoting for disagreement on HN. (Perhaps the people who think this are mistakenly applying the rule from Reddit, a much better-known site.) But that doesn't mean just any kind of downvoting is ok. For example, downvoting a comment that says 2+2=5 is ok (unless it was quoting Dostoevsky!) But downvoting a substantive comment merely because you don't like the same things as the author is not ok. We see this a lot, for example, in programming language debates.
Some users want us to formalize the downvote policy in a precise rule, but we don't have a precise rule. Here's what we do say about downvotes. First, when you see a comment unfairly in the grey, be a good community member and provide a corrective upvote. Most comments that unfairly dip into grey get corrected this way.
Second, when you get downvoted, resist the temptation to strike back. Getting downvoted excites emotion. It stings a little, and the mind recoils from the idea that one might have deserved it. The way to respond as an HN user is to take the hit, review your comment to see what might have evoked it, adjust future comments when you see anything, and shrug it off when you don't.
If you want more clarification of community norms around downvoting, I've been impressed by brudgers' recent few comments on it and by dragonwriter's comments in https://news.ycombinator.com/item?id=9317916. They both did a better job of articulating the function of downvoting on HN than anything we've written ourselves. There is a body of community practice around this, and if you pay attention with the intent of learning it, you will.