That argument that (all of) the Bible is "due to imagination" does not pass scientific muster: the gospels, at least, are almost universally accepted as being legitimate first- or second-hand accounts of some events in the early first century.
Remember, those authors didn't know they were writing "the Bible" - they were writing letters to their friends and neighbors to share what they experienced. They are more like (auto)biographies of "hey we met this guy, and he changed our lives." It isn't fiction.
Now, you don't have to believe the implications of everything they said - but to say it's fiction is to deny what those works actually are.
There are similar academic approaches to the Old Testament books too, including all the allegories and apocalyptic literature. Now apocalyptic (Daniel, Ezekiel, Revelation, etc.) does have fantastic imagery that is fictional, but it's fiction with a purpose. Think of all the books written "in more modern times" that make social commentary. The plot of the stories may be fiction, but the commentary is not - that commentary is real. This is what Bible scholars mean when they say the Bible is the word of God - the social commentary is the true part, not the literal words on the page (which is why people who claim only a single translation is The One are actually wrong, and need to be told that - kindly).
My personal feeling is that people that focus on the actual words are missing out - they're caught in details that don't matter. And that focus on the words, rather than the "heart of God", often generates social unrest, which seems pretty opposite to what Jesus taught about the Kingdom of God, which didn't seem to be characterized by unrest.