On HN we don't consider a post to be a duplicate if the story hasn't had significant attention yet. Otherwise too many stories would languish unseen.

We're working on a way to let users indicate which posts are dupes of one another by submitting their HN ids or urls, so this hopefully won't be confusing for much longer.

And more recently here: https://news.ycombinator.com/item?id=10530149

But it's a great article that deserves some discussion, which it hasn't had yet.