This is "a place to question religious belief systems." There is an implied presupposition here -- admittedly justified in many cases -- that persons with a supernatural faith must _never_ have questioned it before. But in my own case, I _wasn't_ raised in any faith. My arrival at Christian beliefs was the _result_ of questioning, of questioning the agnostic views I had been living by.
God-believers are constantly accused of self-deception; but I can attest that self-deception _precedes_ any organized religion. All of us are born hard-wired with a tendency to believe what we want to believe; this does not just suddenly appear _when_ some faith-system is presented to us.
While I was in second grade, completely devoid then of any supernatural dogma, I had a lot of difficulty with arithmetic. It was embarrassing to me; I didn't _want_ to believe that I was inferior in mental ability to the other children. Therefore, with my little ego uber alles, I tried to _make_ myself believe that the teacher was "against" me. I tried to believe that she was secretly _giving_ answers to all the other children, so that _only_ I would be baffled, and _only_ I would look stupid.
I didn't need to go to a Sunday school to learn how to be delusional. I had a built-in readiness to fool myself. And the very fact that this instinct of automatic self-justification exists in people is _part_ of the reason why the doctrine of "sin" makes sense to me now. In my agnostic years I, as much as anyone supporting this group, would have insisted that I already was "good without a god." This bias toward believing in my own rightness was as blind and stubborn as anything you could point to in churches. And as a skeptic, I had a convenient advantage: I could simply _choose_ to believe that _whatever_ sort of behavior I felt like doing anyway, _was_ the enlightened, highly-evolved moral code I was living by.
It's easy to say that one is morally consistent when one is allowed to make up one's own rules. Like hitting a golf ball, _digging_ a hole wherever it happens to fall, and then _claiming_ to have scored a hole-in-one. But how many of us, if hearing that a business firm or government agency is accused of corruption, will trust that firm or agency to "investigate" _itself_ without answering to any outside authority?