Following up on the post below, as many people suggested, if you're a liberal the press will pick apart your religion because it's somehow "weird." We all know religious means anti-abortion and at the very least not too happy with gay people. If you're Howard Dean or Barack Obama or John Kerry then they'll do anything to suggest that somehow your religion is illegitimate or un-Christian. It doesn't help that there are a bunch of "religious left" consultants running around telling Democrats how they're supposed to talk about religion, as if there's only one "right" way to do it. From a purely cynical political marketing perspective maybe they're right at times, but it sure does suggest a rather narrow view of what's acceptable in this country.
Besides, when Democrats do talk about religion the high poobahs of punditry just ignore them.