assuming the most sensible interpretation

That is pretty much the reverse of what you have been doing.

I think your actual habit is of assuming the interpretation that makes most sense to you. Unfortunately that isn't the same, and in particular it gives very wrong results when your mental model of your interlocutors is very inaccurate.

your argument appears to come down to "arguing 'NRx-type' positions gets makes my side upset therefore the 'NRx' side should stop doing it".

Not quite. (Though, as entirelyuseless says, that wouldn't in fact be such a bad argument.) Here's a link to where I came in; as you can see, I was explaining how having NRx discussions tend to proliferate could be a problem. My answer was that I didn't know whether it actually is, but it could be so in a situation where (1) there are very few NRx's (but vocal enough to have a lot of impact) and (2) most of the other people aren't interested in NRx discussions. And then we got into a lengthy discussion of why #2 might be; rudeness-and-crossness was one of many possibilities.

So the argument is: in this hypothetical situation that may or may not be actual, most LWers don't want to have a lot of NRx discussions. One of the many possible reasons is (as you put it) that these arguments get their side upset. Since (in this hypothetical situation) most LWers don't want these discussions, and very few actively do want them, LWers as a whole would be happier without them.

(Although I've adopted your spin-laden language in the paragraph above, I would like to point out that it's actually quite far from what I meant. My hypothetical person-who-doesn't-want-to-talk-about-NRx is concerned not only that his allies might get upset, but also that his opponents might; and that the result of all this getting-upset on both sides is likely to be that no one learns much from anyone else. That's why the metaphor is "more heat than light" and not just "lots of heat".)