"Interesting" is not the same as "gratifying one's intellectual curiosity." More specifically, and again quoting the guidelines about on-topic:
Anything that good hackers would find interesting.
That includes more than hacking and startups. If
you had to reduce it to a sentence, the answer might
be: anything that gratifies one's intellectual
curiosity.
The audience is clearly intended to be hackers. It could be argued - and I believe and use as my guidance - that this particular paragraph is referring to things that satisfy the intellectual curiosity
of hackers more than it would of non-hackers. In other words, the articles should not only be interesting, but they should be such that non-hackers would not find them as interesting.
On the margins there will always be articles that don't get killed which perhaps should, and articles which should probably survive, but don't. There will be random fluctuations akin to turbulence around the edges.
The Economist article about prisoners ( http://news.ycombinator.com/item?id=1541942 ) might be regarded as something biased in interest towards hackers because people can argue about how to change the laws, or the meting out of punishments - hacking justice. The NY Times article about Jewish conversion is perhaps less biased to hackers because there's nothing for hackers specifically to argue. It's of broad interest to intelligent and politically aware people, and not specifically biased towards hackers.
Personally I'd wish for more clarity on exactly what happens, because then there'd be fewer people speculating and asking the same questions over and over. Also personally, I'd wish for more deeply technical submissions.
But here is a certainty: navel gazing, questions about policy, complaints about submissions being killed, and general moaning about karma, flags and moderators are getting killed faster than I've seen since I arrived. Not everyone shares your exact interests, and if your submission gets killed, move on.