For instance -- if one says that the bits that Jefferson cut out were/are fiction, then on what basis does one say the ones left in are not fiction?
Secondly -- even Josephus confirms the stories of the spread of Early Christians -- how can one call that fiction?
Thirdly -- if one says that the Resurrection etc is fiction, then how does one justify this 2000 or 1800 years after the event? What special knowledge does this person centuries after the event have that the people from the 1st century who witnessed this did not have?
Agreed.
Fourth -- if one rejects Jesus' miracles and resurrection as fiction, then how does one account for the well-documented subsequent actions of his disciples? At His arrest and crucifixion, they were disorganized and demoralized, even denying Him with curses when accused of being followers. Suddenly, they boldly carried His Word to a hostile world, suffering deprivation and persecution - all of them (with the probable exception of John) being executed for their beliefs and refusal to deny that Jesus is the Christ.
What, short of an empty tomb, could be the motivation for such a change?