I've taken a look, and this was a case of what I said: we shadowban accounts when they're new and show evidence of spamming or trolling. In your case, the account was new and had repeatedly broken the site guidelines (using HN for political battle and being aggressive to other users). That's evidence of trolling, which is one of the situations where we shadowban. I mentioned https://news.ycombinator.com/item?id=17358383 by email because that post was what tipped the scales.

I can see why you are angry that we shadowbanned you, because that account went on to make other comments that were fine for HN. Indeed, quite a few were vouched for by other users. That's evidence of not trolling, and that sort of account is not the kind we shadowban—it's the kind where we post moderation replies, and tell people if we ban them. But those later comments didn't exist yet when I shadowbanned you.

Here's the information you need if you want to understand why we do things this way. HN gets tons of new accounts that break the site guidelines and in fact are created for that purpose, which is what I mean by trolling. We can't reply to them all, ask them to follow the guidelines and patiently explain where they're going wrong. If we tried, we'd do nothing else all day—or rather would go mad before getting there. Many of these users know perfectly well what the site guidelines are and have no desire to use HN as intended. If we poured moderation resources there, not only would it not work, it would make things worse, and meanwhile those resources would be unavailable for the rest of the site. For accounts like that, we use shadowbanning, and for the most part that approach works well. But it doesn't work in every case.

When a user emails us about such an account, we have to guess whether they're asking questions in good faith and really want to use the site as intended, or whether there's little hope of convincing them to do so. We don't always guess right. It looks like I guessed wrong in your case. The thing is, though, that when I sent you that detailed explanation of what was wrong with your comments and why we'd banned you, you didn't respond with any indication that you'd received the information and wanted to do something with it. Instead you responded aggressively. I get that you were angry that you had been shadowbanned and didn't know it. But that type of response is correlated with users who go on to be abusers of the site and are not people we can convince to do otherwise, no matter how many replies we give them.

All of this is pattern matching and guesswork. Your original comments and your emails matched patterns that are associated with abuse of the site. With hindsight I see that the pattern matching got it wrong, because your new account has gone on to be (mostly) an ok contributor to HN. (I say 'mostly' because, looking through its history, I still see unsubstantive comments and occasionally worse, but not bannably worse.) But I don't see what I could have done differently in any way that would scale. Our resources are meagre; we're constantly in triage. Patient explanation takes a lot of time and energy—it has taken me an hour to write this so far, and there are many more users demanding explanations than I have hours. Had your emails indicated openness to information or willingness to change, I probably would have replied further. But there are many users who fire multiple angry emails on each reply they get, and we've learned that they are not a good investment, when hundreds of other things and people are clamoring for attention and explanation.

Actually, I do think there is one thing we can do differently that is helpful in such situations: get better at handling anger. There are many users whose every interaction with us is angry and only angry. Often it feels like the intensity of their anger exceeds any of the provocations they're complaining about on HN, even if they're correct on those details. It's as if they're really angry about something else—something more important—but they turn that energy instead onto the extraneous outlet of HN and its moderators, maybe just because it's less important and so in a way safer. I find it difficult to be on the receiving end of this anger. At any moment, there are multiple people doing it. They don't know about each other, so they experience our interactions as individual and demand individual attention, while we experience it as a constant bombardment. It's possible to grow in capacity to handle this—it just requires a lot of personal work. You emailed us a year ago, and I've probably gotten better at this in the last year, so maybe the pattern-matching works a bit better now.