I can only say these things are variables. I have no idea what the weights are. For all I know (I'm sure they tune the thing without publishing details) it now involves some kind of sentiment analysis. But rather that attempting to reverse engineer the process, I recommend getting in touch with HN and expressing your concern - if enough folks feel strongly about this story, it'll be buttressed a bit.
What I'm saying is this is beyond a "weighting" thing. You don't need to know the precise algorithm, but you can make some reasonable inferences (e.g. more votes probably doesn't penalize). If you just watch this story on the front page, it's acting as if it's hard-capped at #10, and where it's happy to stay for a while (though occasionally going to #11 and then coming back). It really looks like someone has interfered with it rather than it being an algorithm thing, unless the algorithm imposes deliberate hard caps on some stories. And given that it seems to have had some manual interference, I'd rather they address this publicly; everyone is entitled to know.
(Update: And just as I finish writing this comment, it's at #13, whereas the following 3-hour-old story with 19 points and 1 comments is somehow at #9 now: https://news.ycombinator.com/item?id=25493577)
