I believe those who wrote the Bible clearly lived in an era would would find abhorrent today. So, why would I want to follow anything that they wrote as being a road map for living today?
You know who does? Crazy Muslims who blow themselves up.
I thought I would make an attempt to answer the bolded question. First, however, I want to acknowledge your concerns. If you asked me who, in today's world, most misunderstands the ancient religious texts, I would answer that it's not atheists, but fundamentalists. I'm not going to try to trace out the genealogy of fundamentalist thought and interpretive apparati--suffice to say it's a fairly recent phenomenon, and bat sh*t crazy, to use an intellectual term.
However, the recent-ness of fundamentalist doctrine should suffice to show practically anyone that the authors of those texts and their audiences did not approach those texts, or the religion they underwrote, as literal. It was well-understood by those ancient peoples that the texts had a history, they were imperfect and incomplete, and written by human beings who had come into contact with a great divine mystery. Some parts were understood as literal history (for example, the Books of Kings--but not the Book of Genesis), but that's about it. The remainder were understood to be the result of human beings with a talent for something largely lost in today's world--the struggle with the juxtaposition of the exterior world and the divine world.
I like to think of the matter in these terms. There is an external, semi-public or quasi-public world, the world that is "out there," apparently distinct from my thoughts, the world in which my body has extension and movement. That external world may or may not be an illusion. Then there is the world "in here," the world in which my thoughts, feelings, judgments, imaginings, etc. exist--the world that they constellate and perhaps constitute. This world, too, may or may not be an illusion.
Apparently, neither world is an illusion--they impress as distinct domains that are porous to causation (rock flies through the air and strikes my head, causing me to feel pain, but the pain is not in the external world. I develop a desire to drink water, so I get up, turn on the faucet, and fill a glass--and these are in the external world).
The internal world is just as interesting as the external world. And it may just be that there is something divine, something unusual and mysterious, to be discovered in that internal world. As if, buried under layers of dreams, fears, intuitions, and the incessant chattering of our thoughts, there is a pure light, a divine fire that is in direct contact with a reality that transcends the individuality of the person that I am.
Religious texts are the records of individuals who explored the deep layers of that interior world and then tried to find ways to express what they found there.
Like the records of early explorers, their words are mythological, perhaps exaggerated, imperfect, and mysterious in themselves. This latter point is the great tragedy, as they were interpretted by those who have little talent for exploration of that interior world to have meanings that they do not have. Also, they are susceptible to fraudulent entries--people sensed some advantage in being seen as someone who could explore the interior world, and they just made some stuff up, and it's hard for others to distinguish the two.
I actually think comparatively few people are capable of being genuinely religious. It's a talent, like anything else--cooking, mathematics, music, athletics, etc. Those who lack the ability should be content to live a good life as a good person doing the things they enjoy and do best. And it's certainly downright foolish, as you say, to try to live in the world in which these texts first appeared.
