Off-topic submissions are a smaller problem here than the kind of complaining you're engaged in. Looking through the HN posts I've upvoted, I see that I've learned things about history, music, language, physiology, mathematics, economics, and psychology, in addition to much about computing and startups. That's obviously the point of the site. People have been complaining about HN "turning into reddit" for a year or more. It hasn't, and it isn't.
The mechanism for politely expressing your tastes is the upvote. I see no evidence that it needs augmenting.
They are, perhaps intentionally, rather fluid and vague. I mean, if you wanted to argue about it, you could say that the problems with Zimbabwe are politics, and certainly aren't new: they've been covering that country's decline for years in The Economist, and if I recall, had one of their reporters kicked out of the country.
Speaking of the guidelines, I don't think anyone pointed out the one that actually addresses the "off-topic police" explicitly:
Please don't submit comments complaining that a submission is inappropriate for the site.
I know this one! Hacking and startups:-) My concern is not 'uninteresting' at all, but the slippery slope that reddit went down, where a trickle of genuinely interesting articles on politics and economics became a flood of crap.
Now if you'll excuse me, I'm going to go find some articles about Nietzsche's "eternal recurrence" to post here. :)
I quite enjoy it. I find those articles interesting, though the debate is usually less so. Yet I'm a hacker. Does that mean that reddit is publishing hacker news?
Of course not.
Just because it's interesting to "some hackers" doesn't make it hacker news. Similarly, if an article about fluffy toys is interesting to some people in the medical profession, should it be published in the British Medical Journal, as a medical article? No.