If you agree that it's the message and not the details or the facts of the persons in the stories, that are the important thing, then why does it matter to make an argument to convince people that the stories in the gospels are about historical facts? If the message is what matters, then why focus on proving things historically in order to have faith?
Isn't that missing the point of the gospels themselves? Wouldn't that be like having a debate that the Good Samaritan is based upon a historical event, and you need to prove it to the skeptic in order for them to believe that we should care for others outside of our own in-groups? Isn't trying to prove that the earth is 6000 years old, when all the evidence shows that it's not, or that evolution couldn't possibly be true because it's not spelled out scientifically in the book of Genesis, missing the point of the entire story itself? You see my point here?
It's the meaning of the message, through the stories themselves, either based on real events in whole, in part, or totally made up, that matters. Arguing for the events to be facts in order to believe the message of the story, is a distraction from the message itself.
I would go further than that, and say that those who place the kingdom of God in some future time or place, after this life, after the end of the world, are missing the point that God is Present in this world right now, in everyone's life, if they care to access that for themselves, here in this world, in themselves, right now. The purpose or rather the message, is not "it comes later", but it comes now.