1. There are no mistakes, so the premise of your question is flawed.
2. I believe it, and it's the only book to have endured as long as it has and adopted so many followers.
3. I don't disregard any parts of it, so again the premise of your question is flawed.
4. Because He trusts man. He knows that humans can understand human concepts. Perhaps Hid concepts are for too difficult for us to understand so it needed to be 'dumbed down' for human literacy.