(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.
First of all, the there is the meta-level issue whether to engage the original version or the pop version, as the first is better but the second is far, far more influential. This is an unresolved dilemma (same logic: should an atheist debate with Ed Feser or with what religious folks actually believe?) and I'll just try to hover in between.
A theory of justice does not simply describe a nice to have world. It describes ethical norms that are strong enough to be warrant coercive enforcement. (I'm not even libertarian, just don't like pretending democratic coercion is somehow not one.)
Rawls is asking us to imagine e.g. what if we are born with a disability that requires really a lot of investment from society to make its members live an okay life, let's call the hypothetical Golden Wheelchair Ramps.
Depending on whether we look at it rigorously, in a more "pop" version Rawls is saying our pre-born self would want GWR built everywhere even when it means that if we are born able and rich we taxed through the nose to pay for it, or in a more rigorous version 1% change to be born with this illness would mean we want 1% of GWRs built.
Now, this all is all well if it is simply understood as the preferences of risk-averse people. After all we have a real, true veil of ignorance after birth: we could get poor, disabled etc. any time. It is easy to lose birth privileges, well, many of them at least. More risk-taking people will say I don't really want to pay for GWR, I am taking my gamble tha I will be born rich and able in which case I won't need them and I would rather keep that tax money. (This is a horribly selfish move, but Rawls set up the game so that it is only about fairness emerging out of rational selfishness and altruism is not required in this game so I am just following the rules.)
However, since it is a theory of justice, it means the preferences of risk-aversge people are made mandatory, turned into a social policy and enforced with coercion. And that is the issue.
Now, how could Rawls (or pop-Rawlsians) get away with that? By assuming that all reasonable people are risk-averse anyway. In other words, turning risk-aversity into a tacit norm. Instead of seeing it negatively as a vice, or neutrally as a preference, it is basically a virtue here. Now, we have a perfect name for turning timidity into a norm: it is called cowardice.
And I think my argument managed to demonstrate avoiding in politics mind-killing up to the last sentence when I used a connotationally loaded word (cowardice), but at this point I had to, as I casually remarked earlier I feel this way about it and now had to explain why. But the last sentence refers only to my feelings and not an integral part of the argument, for the argument , just stop reading at "risk aversion should not be made into a norm and coercively enforced calling it justice".
Again, it is not part of the argument, but an explanation of my feelings: when I try to improve one my vices or weaknesses, and I see others almost see them as norms, I feel disgust. For example, willful stupidity disgusts me - I think this feeling may be common around here. But as I am also trying to work on my own cowardice, being too accepting of it also disgusts me.
Thanks for the explanation. Do you have any alternatives?