A long blog post explains why the author, a feminist, is not comfortable with the rationalist community despite thinking it is "super cool and interesting". It's directed specifically at Yvain, but it's probably general enough to be of some interest here.
http://apophemi.wordpress.com/2014/01/04/why-im-not-on-the-rationalist-masterlist/
I'm not sure if I can summarize this fairly but the main thrust seems to be that we are overly willing to entertain offensive/taboo/hurtful ideas and this drives off many types of people. Here's a quote:
In other words, prizing discourse without limitations (I tried to find a convenient analogy for said limitations and failed. Fenders? Safety belts?) will result in an environment in which people are more comfortable speaking the more social privilege they hold.
The author perceives a link between LW type open discourse and danger to minority groups. I'm not sure whether that's true or not. Take race. Many LWers are willing to entertain ideas about the existence and possible importance of average group differences in psychological traits. So, maybe LWers are racists. But they're racists who continually obsess over optimizing their philanthropic contributions to African charities. So, maybe not racists in a dangerous way?
An overly rosy view, perhaps, and I don't want to deny the reality of the blogger's experience. Clearly, the person is intelligent and attracted to some aspects of LW discourse while turned off by other aspects.
This is harsh, but I think it's basically right. A useful rule of thumb: any time you see the words "safe space" used in the context of deliberation or political discussion (as opposed to, y'know, providing actual, safe, spaces to people threatened with actual bodily harm) you can substitute "echo chamber" and see whether their argument still makes sense. Yes, sometimes echo chambers generate worthwhile political arguments, but that's kind of the exception, not the rule. And these arguments still need to be evaluated openly, if only because this is the only way of acquiring durable credibility in a political or deliberative context.
I agree about political discussion. But LessWrong isn't about political discussion. Far more important to a typical LessWronger would be something like community building, which correct me if I'm wrong but that's pretty much a textbook example of what "safe space" is good for. This criticism was not directed at us per se, but we can extract useful information from it.