The fact of the matter is, humans lie all the time, they just don't realise it. Even crows and primates lie to each other in their way and this is the surest means of establishing social cohesion. Now there are lies and there are, LIES. So the metaphor, which is kind of a lie, is a story approach to writing the Bible and was necessary for the time, place and culture of the times.
Today there are few excuses for interpreting much of the Bible as literal, but there are those who through no fault of their own, do struggle with the concept of the metaphor.
The next thing that is worth considering is that there is a specific part of the brain that deals in abstract concepts, metaphor, allegory, which are abstract concepts, along with words, numbers and everything concerning the nature of God, the human spirit and most of the teachings in the Bible. Now my point is that some people can simply not grasp a metaphor or an abstract concept, which leads to literal beliefs in Genesis, which then inoculates those who understand metaphors from looking into certain religions.
That doesn't mean they are silly, it's the hand you draw in life. Those with an overly active brain area dealing with abstraction become artists, novelists, creatives in general. Beneath that are varying degrees of understanding abstraction. That's why it's almost impossible to convince a fundamentalist believer with empirical evidence that scripture is symbolic and metaphoric. Now this is a generalisation, but I'm willing to bet from my observation of the type of person attracted to fundamentalist religions, that they are not good at working with abstract concepts. They can be very black and white.
As for Jesus, I think Copperbod answered you well. Clearly He existed, but also clearly He was nothing like the Jesus made in the image of today's believer.
