I don’t think it has anything to do with mod intervention. I think part of it probably has to do with some sort of exponential mathematical thing, that if you have ten liberals, and they tell their friends, and then they tell their friends, about fluther, then you have a bunch of liberals on the site. I also think liberals tend to be more open minded, tend to like to debate, and like to learn different points of view, so they are more likely to enjoy a site like this. Also, scientists, who are attracted to a scientific method of questioning, and proof, like discussion, makes sense they would like a site like this, and scientist tend to be atheists, or at minimum question.
People who follow their religion lock step and their political leaders in the same way, generally are not the type to question, and prefer to be around the people who think exactly like themselves, and I think prefer not to debate topics. We do have people on fluther who are conservative both religiously and poltically, and I for one am glad to have them here. Glad to be able to find out from them how they think, glad they are willing to discuss politics, religion, how they view the world, and various issues. Generally our Jellies who are more to the right on such topics still are willing to discuss, obviously, and share their point of view, so they do not fit into the category of people I was describing above.
@Vortico What do you mean?