The problem is that people who are uncritically accepting stuff they have no actual proof for, yet who see themselves as skeptics, are able to convince themselves that they are merely engaged in rational thought when they are not.
As an example I offer http://www.amazon.com/The-Moral-Landscape-Science-Determine/... by Sam Harris. Absolutely none of his moral claims make any sense without first accepting parts of his moral view that he fails to even question. In fact he uses an unquantified quantity called "well being" as justification for his theory. Yet the only scientifically supported definition for well being for living things is "evolutionarily successful". And by that measure, being religious and scientifically ignorant is very good for you!
Yet his reasoning is utterly compelling to himself, Richard Dawkins, and many other "skeptics".
And yet self-claimed skeptics frequently uncritically accept all sorts of things that they have no actual proof for. (He calls several of these out.)