Agreed. I've been thinking about how communities can handle this problem for awhile. A solution to it would be revolutionary, in a very good way for the entire Internet, and what better place to experiment with and develop a solution than HN. Here's my over-ambitious shot at a solution, based only on experience in online communities:
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I propose that we have different rules, much higher standards for commenting, for hot button issues. When these situations come up, our moderators could post something like,
** Hot button rules apply **
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1) Be precise: Who? Did? What?
Who should be a proper noun; only individuals (and in some cases, specific organizations like 'Acmesoft') actually have thoughts, motives, and perform actions; groups do none of those things - we are not hive minds. This eliminates lazily broad statements with huge implications that provoke anger and fear, stereotype large groups, and don't make us any better informed. 'Tennesseans hate Kentuckyians' doesn't inform anyone - there is nothing all Tennesseans agree on, and nobody can possibly read all their minds, and we know nothing more after reading it than we did before - but '60% of Tennesseans who responded to this survey say they have stopped visiting Kentucky' is fine.
Did: HN readers mostly grasp empirical science and should be able to understand: Only actions are observable, not other people's thoughts and feelings - though you can observe what they say about their thoughts.
What, used precisely, eliminates sloppy characterizations. 'Tennessee Governor Jane Jones despises Kentucky BBQ.' No, what actually happened? 'Tennessee Governor Jane Jones said, "I despise seeing Kentucky BBQ taking jobs from hardworking Tennessee chefs."'
Finally, Be precise also means: No hyperbole.
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2) Context is required: Where and when
Where and when are essential context. Think of your high school writing guidelines: Who, what, where, when, etc. 'Tennessee Governor Jane Jones said, "I despise seeing Kentucky BBQ taking jobs from hardworking Tennessee chefs."': It is essential to know when she said that (1985? 2010? Before the Kentucky-Tennessee trade war began or after?) and where (On a campaign stop in a TN BBQ restaurant? The title of a book? A tweet? A warm-up joke for a speech?); otherwise, we have no idea what really happened.
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3) Back it up:
The burden of proof is much higher, and on the commenter: Respected scholarly research (not someone's self-published book) or highly respected news media, and not in a column or editorial. Wikipedia's Reliable Source rules may help here, but with higher standards for sources (and also actually applied here; Wikipedia articles often ignore the standards).
https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources
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4) Be 100% respectful, as if talking to someone important to you whom you respect. No exceptions; no grey areas; stay well away from this line.
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5) The only idea we don't tolerate is intolerance itself. See Karl Popper's Paradox of Intolerance if you want to go deeper on this. Or a simpler way to approach it: Tolerance is a social contract - you tolerate me and I'll tolerate you.
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6) These rules apply to anyone you quote, also. You can't say 'Kentuckians suck', and you can't quote someone else saying it (except to talk about the quoted person's habit of broad stereotypes).
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Comments violating these guidelines are immediately, mercilessly killed dead. Busy moderators may not have time to explain why, but in most cases you can find the reason(s) here pretty easily. Feel free to rewrite according to the guidelines and try again.
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By now you may be thinking: 'With those standards, I won't have much to say on inflammatory topic X!' or 'Those will be much shorter threads!' or 'I'd really need some good information and think it through in order to comment!' Good; you understand. Imagine if we restricted those discussions to only valuable, informative content. The contents of the threads could actually advance our knowledge about inflammatory, often very important, issues. It's almost hard conceive of. We could actually, in the heat of an issue, advance rational public discussion - a goal that has seemed so intractable that it's almost forgotten; it seems almost fanciful. The perfect challenge.
It also eliminates the prominent problem of people making endless wild allegations for others to refute (see rule #3 - they must back up what they post). So instead of endlessly repeating the same low-value information back and forth, we'd actually gain real knowledge from each other. And if some threads are very short, then what have we lost? A bunch of low-value comments from uniformed commenters? Ideological rants? Things we've heard a thousand times before? It even will save some disk space and bandwidth, and reduce page load times.
Finally, if it works - which not at all a sure thing and will require fine-tuning at the very least - the concept could be used by other online communities. What we develop here - not software, but guidelines for community interaction - it could change the world, in a way that it badly needs and longs for.