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?)