More than that, a poll about fears is likely to have a pretty high false positive rate - just considering the question is likely to bring up a significant number of instances of anything you fear at all, and if it is phrased as generically as "often" with no definition? Getting at the true numbers would require.. Uhm. No, asking people to monitor their fears would be Nigh-certain to make them much more fearful ("log thoughts of sex" has been tried. The results that came back were blatantly a case of "dont think of a pink elephant" coloring everything) and thus would be deeply unethical. I think the cleanest lift would be a large collection of extensive daily journals, or outright annotated lifelogs. That would probably make your subject pool more introspective than the general population, but it should not skew these specific numbers much. Expensive, however.
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.