hard to be frankly dispassionate when you're affected by an issue. That tends to encourage self-serving passion.
Oh, that's quite right. But the original question here is whether they'll even want to join the conversation at all. To me, it's not at all clear why they wouldn't. (And I see this as a mixed bag from a goals perspective, for reasons others have pointed out.)
Because life, of which the Internet is a subset, of which LW is a subset, is full of blowhards who will tell you all about your problems and how you should solve them while clearly not having a trace of a clue about the topic, and life is too short to go seeking them out.
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.