It seems to me that the further back in religious history one goes, the more acceptable it is to apply the "metaphor" principle to an event. Or rather, perhaps I should say in all fairness, a supposed event. Take, for example, the idea that the resurrection of Jesus was only a "metaphorical" event. A teaching kind of story, like the fable or fairy tale with a moral, a lesson to be learned. Now there are certainly good stories with good lessons, even inspiring stories with inspiring lessons. Perhaps this is one of them. Would it matter?
I think that it is of course much safer to apply the metaphor principle to events distant in time. However, I see no compelling reason why, for example, I shouldn't tell you that Mother Teresa never cared for the poor. After all, the stories you have heard about Mother Teresa are really just that - inspiring stories with a moral, designed to teach you and inspire you. Actually, she never lifted a finger to do the things which you think she did. She simply read an inspiring story (which never happened in physical reality), and decided that the proper response was to create a new inspiring story (which never happened in reality)...
To be continued... Really.
BTW, what do you think of this video (h/t Pete Rollins)
And if you are looking for more, you might want to check out this event here in Edmonton, which I think will provide lots of food for thought & discussion: