Very nice observation, Metis. I think you cover the main points:
1) teach others what to believe about G-d - this is well stated. However, what can we realistically teach others what to believe about G-d when we know almost nothing for certain about him / her ?
2) how to behave accordingly - to me this is the real essence of the Bible. It teaches us how to behave ethically and morally.
Thanks, Avi, and let me try to deal with your questions.
I mentioned standing back from the "trees" a bit to better see the "forest" in regards top scripture, but now I'm going to use the same analogy in taking an ever bigger step back. No matter how one regards a theistic or a non-theistic approach, we are what we are, and the world is what it is. But let me focus on what it means to be "human".
As humans, we have certain tendencies, such as socialization, intelligence, compassion, empathy, helping one another, etc.; and much of this appears to be genetic. Yes, there's also some other aspects within us as well that may have negative repercussions, such as anger, parochialism, self-centeredness, etc.
These impulses are there for a reason, including even the ones that may affect us and our society negatively if we're not careful. So, to me, the key is not to deny these impulses, but to try and channel them in more positive ways.
An example is that if I get really angry, instead of lashing out or bottling things up inside, I go for marathon walks until I settle down. If my eyes twitch, I know I'm under stress, which then tells me I must do things to alleviate that in a non-destructive manner, and there's several techniques I use that work for me, but maybe not for you.
To me, a great many of the teachings found in Torah and halacha are pretty much common sense approaches that can help us individually or as a group, but not all teachings are equally useful, imo. Therefore, to me, I'll pick and choose which seem to work the best and go from there. Are these "divinely inspired"? I have no idea, but either way many of these are useful and have helped to make us what we are as both individuals and also a Jewish society.