LW's implicit philosophy (which I don't disagree with) is that a cost of participating is that you are fair game for blunt criticism. Alas, such a philosophy probably repels some potential participants who would otherwise make intelligent comments.
Driving out the voices of the less privileged is potentially problematic when LW claims to be on a mission for the good of all of humanity.
Or to math this up, our mission is unlikely to succeed if we make joining harder and less pleasant for ~54% of the population (51% female, ~2-3% non-hetero male)
So, while agreeing with the principle of favoring open and blunt discourse, I for one intend to make more of a concerted effort to square the circle of being honest and blunt while being more welcoming.
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:
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.