I haven't seen the documentary, but will say that many folks opposed to Christianity (just what I'm citing for reference, could be applied to any or every religion & then distilled further to specific denominations and sub-denominations) pick and choose what they base their entire opposition on. Sure, some Christians think the earth was created in a literal 6 days 6000 years ago. Not all do; many see the story as a parable, as they do with many other things in the Bible. It's just not so simple.

But I'll also agree that many people grow up with what they're told to believe, don't question it, and say they believe it but don't know what they say they believe or don't really believe it even if they understand. I'll use Hell as an example: the modern belief of hell as a place of Eternal Conscious Torment (ECT) is something many Christians say they believe. Very few actually believe it. Why? Because if they did believe it they'd stop everything they were doing and make it their entire life's mission to work their ass off to save even just one single person from going there. If they didn't they'd be a sick, depraved, evil individual that would be worthy of such a place, and there are few of those type of depraved people so the explanation is they don't believe in that thing they say they believe in.

This all said simply -- it's so much more nuanced than people say. I'm firmly Christian but not fundamentalist and have more doubts and questions than I do answers, which is actually fits very comfortably into an approach to faith when one doesn't approach faith as "the place" where all of their questions are given certainty and packaged answers. Ask away if this raised questions about what I mean and I'll do my best to find the time to answer.