I know what you mean about the sub-sect of any faith – as I do believe they exist within every group of believers and non-believers – that possess a kind of self-justified absolutism. I must also say that your respective humility with regard to your own views is encouraging. Thank you.
Really, I believe it boils down to being essentially close or open-minded. It is altogether possible to say, “This is my belief. There are aspects of it which I myself do not yet understand, and which I am prepared to discuss with others, maybe even be convinced differently about by others, yet I can still remain true to that belief.”
One of the snags with the Christian bible is that it isn’t really a book. It’s a library, or an anthology. It contains poetry, philosophical treatise, folk stories, and first-person historical records. Some books in it are meant to be taken literally, and viewed as accurate testimony of real events. (Note – meant to be taken literally. I am not claiming their authenticity myself, but merely the intention of the authors.) Other books were not intended to be literal, historical texts, even when they were written.
So a big problem that many people have, both Christians and non-Christians, is a misunderstanding of this, and a belief that it is, as you said, all-or-nothing. I believe than an analysis of the Christian bible is far more complex than that. Comparing, say, the opening chapters of Genesis with the Gospel of Luke, is just plain wrong.
And as for that good ol’ “knock on your door” factor, while I don’t believe that’s the best way to share one’s faith, I can at least understand where they’re coming from. The chief difference between an atheist and a theist in this regard is that the theist actually has both a moral imperative, and in many cases, and explicit imperative within their creed, to share their faith with others. They do it (most of them, anyway) because they honestly believe it is right. For this fact alone, I like to cut them some slack.