Over on Facebook a friend posted a meme comparing the bible to Greek mythology, and suggested that there weren't any differences. Needless to say, I had to respond. Here's what I wrote. Enjoy!
Well...a good portion of the bible is just a history lesson, telling events that really happened. While the early stuff is a bit questionable (like the whole creation thing), and lots of the juicier stuff like Noah and Samson are obviously borrowed from other cultures, there's quite a lot of it that is historical.
In fact, the big question isn't why the bible's so fictional, but rather, why the hell it's so damn boring. Until the Jesus parts, it's not even particularly mystical or spiritually enlightening. No one would start a modern religion based upon the contents of the Old Testament. No one.
That's why everyone focuses on the fun stuff, like how rainbows didn't exist before God invented them for Noah (presumably light didn't slow down when passing through water until then). Because when you're down in the weeds reading about Tobit, son of Tobiel, whose father was Hananiel, the son of Aduel, son of Gabael, who belonged to the family of Asiel of the tribe of Naphtali, it's time to turn back and read about how Samson played tricks on the Philistines again.
(And yes, that was a real thing, from a page I found at random in my bible. In the Book of Tobit, of course.)
And the point is that the bible does such a good job of interweaving fact with fiction that it can be understandable how someone could grow up believing this stuff. When the Ancient Greeks heard the Odyssey, they knew it was fictional. But in the bible, they can read Jesus' words and learn about what King David did, and these are real things...probably. And yeah, the parts about divine intervention are obviously a bit iffy, but it does make the stories far more compelling.