I am also a logical person and appreciate your post and your points. This is a great topic for more discussion, and could be an excellent thread.
The rule as it is stated is simply a request to treat people with respect. If you'd like to argue specific components of a belief system; GREAT! Organized religion as a whole is full of strange contradictions and deserves questioning. As long as they can stay debates rather than nasty arguments, no prob. That's the point of the rule (just needed to make that clear ).
Okay... now that THAT'S out of the way!

I think that while each of us is free to choose our belief system, we are still products of our upbringings, and that includes how much we are even told about the content of other religions while we are young. I always say that one does not truly become an adult until one has risen above the way he or she was raised, and lives a life making decisions based on what is the right thing to do in this situation AS I SEE IT, not 'is this what Mom would have done?' Sure, we often end up making the same decisions as our parents, including picking a religion, but there's a difference between doing in because 'that's the way I was taught' and doing it because it's right, and it just so happens that your parents would have agreed with you. Get my drift? So if you were raised Catholic, and still consider yourself one today, is it sort of by default, or is it because seeing the other options, you made an adult decision to continue on?
My couple cents on the matter anyway.