(I hope that is the least click-baity title ever.)
Political topics elicit lower quality participation, holding the set of participants fixed. This is the thesis of "politics is the mind-killer".
Here's a separate effect: Political topics attract mind-killed participants. This can happen even when the initial participants are not mind-killed by the topic.
Since outreach is important, this could be a good thing. Raise the sanity water line! But the sea of people eager to enter political discussions is vast, and the epistemic problems can run deep. Of course not everyone needs to come perfectly prealigned with community norms, but any community will be limited in how robustly it can handle an influx of participants expecting a different set of norms. If you look at other forums, it seems to take very little overt contemporary political discussion before the whole place is swamped, and politics becomes endemic. As appealing as "LW, but with slightly more contemporary politics" sounds, it's probably not even an option. You have "LW, with politics in every thread", and "LW, with as little politics as we can manage".
That said, most of the problems are avoided by just not saying anything that patterns matches too easily to current political issues. From what I can tell, LW has always had tons of meta-political content, which doesn't seem to cause problems, as well as standard political points presented in unusual ways, and contrarian political opinions that are too marginal to raise concern. Frankly, if you have a "no politics" norm, people will still talk about politics, but to a limited degree. But if you don't even half-heartedly (or even hypocritically) discourage politics, then a open-entry site that accepts general topics will risk spiraling too far in a political direction.
As an aside, I'm not apolitical. Although some people advance a more sweeping dismissal of the importance or utility of political debate, this isn't required to justify restricting politics in certain contexts. The sort of the argument I've sketched (I don't want LW to be swamped by the worse sorts of people who can be attracted to political debate) is enough. There's no hypocrisy in not wanting politics on LW, but accepting political talk (and the warts it entails) elsewhere. Of the top of my head, Yvain is one LW affiliate who now largely writes about more politically charged topics on their own blog (SlateStarCodex), and there are some other progressive blogs in that direction. There are libertarians and right-leaning (reactionary? NRx-lbgt?) connections. I would love a grand unification as much as anyone, (of course, provided we all realize that I've been right all along), but please let's not tell the generals to bring their armies here for the negotiations.
Well, as for me, reading half the sequences change my attitude a lot by simply convicing me to dare to be rational, that it is not socially disapproved at least here. I would not call it norms, as the term "norms" I understand as "do this or else". And it is not the specific techniques in the sequences, but the attitudes. Not trying to be too clever, not showing off, not trying to use arguments as soldiers, not trying to score points, not being tribal, something I always liked but on e.g. Reddit there was quite a pressure to not do so.
So it is not that these things are norms but plain simply that they are allowed.
A good parallel is that throughout my life, I have seen a lot of tough-guy posturing in high school, in playgrounds, bars, locker rooms etc. And when I went to learn some boxing then paradoxically, that was the place I felt it is the most approved to be weak or timid. Because the attitude is that we are all here to develop, and therefore being yet underdeveloped is OK. One way to look at is that most people out in life tend to see human characteristics as fixed: you are smart of dumb, tough or puny and you are just that, no change, no development. Or putting it different, it is more of a testing, exam-taking attitude, not learning attitude: i.e. on the test, the exam, you are supposed to prove you already have whatever virtue is valued there, it is too late to say I am working on it. But in the boxing gym where everybody is there to get tougher, there is no such testing attitude, you can be upfront about your weakness or timidity and as long as you are working on it you get respect, because the learning attitude kills the testing attitude, because in learning circumstances nobody considers such traits too innate. Similarly on LW, the rationality learning attitude kills the rationality testing attitude and thus the smarter-than-though posturing, points-scoring attitude gets killed by it, because showing off inborn IQ is less important than learning the optimal use of whatever amount of IQ there is. Thus, there is no shame in admitting ignorance or using wrong reasoning as long as one there is an effort to improve it.
I think this is why. And this has little to do with topics and little to do with enforced norms.
I like your example and "learning environment" vs "testing environment".
However, I am afraid that LW is attractive also for people who instead of improving their rationality want to do other things; such as e.g. winning yet another website for their political faction. Some people use the word "rationality" simply as a slogan to mean "my tribe is better than your tribe".
There were a few situations when people wrote (on their blogs) something like: "first I liked LW because they are so rational, but then I was dis... (read more)