I hate to say this, but...
psssssssssst, it's a MOVIE.
Not an historic record, not a "proof" of anything. Nobody alive today knows what really happened. This is one possibility. One of an endless amounts of possibilities, including that it NEVER happened the way most Christians believe it, that it NEVER happened the way anyone else believes it, and it's entirely possible that it just may have happened EXACTLY how most Christians believe.
My take on the whole religious idea... I think I believe there WAS a man named Jesus, was the son of Joseph, was a carpenter, possibly a philosopher, maybe even some sort of magician. Was he the Son of God? I dunno. I guess anything's possible. But, if my friends and I wrote a book now, buried it for a few thousand years, and it was "historically accurate" as far as names and locations existing, would someone take it as another form of the Bible? In the time of its writing, there was no real way to verify the events, save for 4 men writing different versions of essentially the same story. The rest is quite possibly a fever dream (Revelation) or a handful of zealots/madmen who were freaks over this guy... I've seen enough people praising Elvis in my lifetime to assume that he could be some sort of god. The way I see it, take enough base in reality, create a wonderful story, toss in some moral twist, some incredible fiction/miracle, and voila, you've got enough of a story thata is historically/geographically truthful that the rest "just might have happened, too" in a lot of people's eyes.
My big question comes in the form of what is NOT told of Jesus in the Gospels... we never see him as a teenager, or even a very young adult. He jumps in age from VERY early teens (12 or so) to about 30, shortly before the time of his death. Why is this nearly 20 year span painfully clearly absent from not 1 or 2, but, ALL 4 Gospels, yet the rest of the material was found in tact enough to be published? Seems a little... fishy to me, if you'll pardon the pun.