Usually this happens when a post touches on some sensitive political topics; people then start flagging it for no reason, presumably because they just don't want to see the topic discussed.
Such flags are for the most part quite in keeping with the site guidelines. If weren't for them, HN would be a political / current-affairs site. It's true that sometimes the flags go too far; in such cases we sometimes turn off the flags, if an article is particularly on-topic and/or capable of supporting a substantive discussion.
I'm not convinced that we can do much better than that. Turning off flags or weakening them would be weakening the immune system. We need the immune system. Yes, the system has failure modes; correcting for the failure modes of the system is what moderation exists for. https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
Yes, this doesn't at all disagree with my comment; browsing /new for a while, it is very obvious that most of the time, flagging is used to filter out spam and off-topic posts. However, it is certainly a thing that happens that on-topic posts, specially those covering topics where technology and politics intersect, often get down-voted if they touch on certain topics.
Mind you, I am specifically talking about posts that have already started spawning on-topic conversations in the comments. Overzealous and politically motivated flagging is definitely a thing that happens on HN, and the tool to combat it (showing dead posts and vouching for them) are much better hidden than the flag button.
