This could be because they got caught in a spam filter, or because we banned them and the comments they've posted since then are better. In such cases we're always happy to take a look and unban the account if they're using HN as intended.
There are some weird edge cases, like sometimes a banned user, once they're unbanned, will revert to posting abusively. Then we ban them again and they revert to posting good comments again. Who can fathom the psyche of homo internetus.
It's also common for an account to post both fine comments and abusive comments. It's the latter that determine whether we have to ban the account—that's how rule enforcement works. But if a banned account posts something good, there's no reason why the good post needs to remain [dead]. This is what vouching is for: https://news.ycombinator.com/newsfaq.html#cvouch.
Thanks, I didn't know about vouching. I guess there's indeed an history behind each ban of a real user. (Not talking about spam of course, it's a different thing)
Sometimes the history is “your account was pretty new so when you posted something a lot of people didn’t like we assumed you were a troll, banned, and never looked again”.
There are some weird edge cases, like sometimes a banned user, once they're unbanned, will revert to posting abusively. Then we ban them again and they revert to posting good comments again. Who can fathom the psyche of homo internetus.
It's also common for an account to post both fine comments and abusive comments. It's the latter that determine whether we have to ban the account—that's how rule enforcement works. But if a banned account posts something good, there's no reason why the good post needs to remain [dead]. This is what vouching is for: https://news.ycombinator.com/newsfaq.html#cvouch.