There is no doubt that the gospel writers were deficient in revealing their sources... However they hadn't been to Journalism school and most modern journalists are deficient as well.

Biblical writers had no problem diseminating oral tradition as fact without the need of support. The Old Testament is far more problematic. A greater support for the truthfulness of the gospels comes from the lack of opposing material from the same time period.

The use of Josephus and other classical historians is questionable. We use them because we don't have anything better.

I haven't seen the movie yet, however I look foward to seeing it soon. I simply respond because the validity of the biblical text is interesting to me and there are difficulties to discuss. However the difficulties are not as conclusive as some would imply.
(This by the way is not directed at my honorable friend Mr. Faulk.)