I’m not sure how OP decides whether to x-post something from HN (manually? randomly? vote threshold?). But in the Matrix example it’s pretty common for HN users to post a project page as the article and then use the comments to discuss the project. In this case it looks like a fair number of users upvoted it but no one had anything to say.

It does seem confusing now that I think about it, if you aren’t familiar with HN. It has its own weird little culture and rules. I generally like it there most of the time.

If you click the [comments] link instead of the post link, it’ll take you to the HN comment section which is often more interesting than the article.