I don't know the specifics of the HN submission filter, but if you spend any time on /new you'll see how often the same content gets submitted over and over again, which often results in flags. Additionally, new accounts and low-reputation accounts also tend to have their submissions flagged by default, and require a "vouch" to be unflagged.

In other words, HN's submission filter is fairly aggressive, I doubt anything nefarious is taking place.

dang commented here[1] that "Users are flagging them. The only thing moderators have done is decline to turn off the flags."

I doubt there's a conspiracy of users flagging them, either, so you're most likely correct.

[1] - https://news.ycombinator.com/item?id=26561855

Not only is this a very interesting story, but it's still developing and there isn't much to discuss until we hear the next development.

In other words, is Reddit telling the truth when they stated it was autoban mistake?

They were all links to active threads. This is the first link to an article on the topic.

Well, https://news.ycombinator.com/item?id=26557175 was also flagged when the post was getting popular. HN has really been going on a censorship spree lately as well. What's even worse with HN is that sometimes your comments appears to have been posted, but if you log out or go in private browsing, your comment cannot be found at all!

Users tend to flag stories. The system also has a kind of automated flame detection system. The moderators can override both.

Just consider HN to be actively moderated. It's an opinionated community that does not strive to be a democracy.

Now this post is on page 2 as well.