That said, I have no idea what could be done about it.
I hesitate to suggest this, but I've noticed most of the "sensitive but discussed anyway" issues have been on areas where socially weaker groups might feel threatened by the discussion. Criticism of socially strong groups is conspicuously absent, given that LW demographics are actually far-left leaning according to polls.
If the requirement that one must be dispassionate would cut in multiple directions simultaneously (rather than selectively cutting in the direction of socially marginalized groups) then we'd select for "willing to deal intellectually with emotional things" rather than selecting for "emotionally un-reactive to social problems" (which is a heterogeneous class containing both people who are willing to deal intellectually with things which are emotionally threatening and people who happen to not often fall on the pointy end of sensitive issues)
The reason I hesitate to suggest it is that while I do want an arena where sensitive issues can be discussed intellectually without driving people away, people consciously following the suggestion would probably result in a green-blue battleground for social issues.
There's lots of talk about religion which is almost the definition of a socially strong group.
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.