No, I'm saying that if you systematically repel people with different experiences from your own, you'll get more groupthink.
More pointedly, if you exclude people who have had a particular experience from your discussion, but try to draw conclusions about those people's experiences, abilities, opinions, or motives, you're probably going to get clueless results — or at least, results that do not reflect a serious inquiry. (For instance, look at groups of atheists who speculate about how "insane" religious people are; or an exclusively-male group speculating about What Women Want. If they were actually interested in acquiring facts about the experiences or motives of religious folks or women, wouldn't they care to listen to some?)
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.