[TeMPOraL]

Here's another explanation: not all bad stories are upvoted, just those that work well to spin up a good discussion.

I know I upvote in this pattern. I read HN for comments first, stories second. The linked story is immaterial, as long as there's something interesting in it that can be discussed on a better level. Take "pop science" articles - the comment thread under those tends to contain links to original research, corrections to the article, opinions of actual scientists in the field, and much better explanations of the described phenomena (as well as the standard set of complaints about paywalls and "journalism these days"; I myself am sometimes guilty of the latter).

Would an arXiv paper be preferable to a "pop science" article? Perhaps. And we get our fair share of papers submitted here too. But I have a feeling that the "articles for the masses" are statistically more likely to create an insightful comment thread, and end up being upvoted more.

Also worth noting is that moderators often update the submission link, when better sources on the same topic are surfaced.