This “why?” pertained to my statement that questions of motivation are necessarily uncertain, but valid, nonetheless. Let me give one example, that favors the historical reliability of the Gospels – in-fighting and disagreements between the early Christians. The Acts of the Apostles chronicles disagreements between Peter and Paul, I believe. Paul’s letters are replete with reprimands and with calls for unity.
These are the kinds of details that are not likely to be made up; for what would the motivation be for airing quarrels and disagreements between the early Christians? What motivation would there have been to make these things up?
With the miracles, it is different. There
would be the reasonable hazard of a motivation to exaggerate Jesus’ powers, as a way of convincing readers that “surely, this was the Son of God.” This is not to say that the miracle accounts are thereby disproven; but, rather, there is a hazard of motivation there (just as there is a hazard when a mother tells you, “I have the most wonderful, smartest, gifted, talented boy in the whole class”).
A similar hazard exists with reading the Old Testament backwards; in other words, finding things that
had to happen for the Jews to believe that Jesus was the Messiah, and making them fit. Thus, the genealogy of Matthew, tracing Jesus back to the house of David; or Jesus’ being born not in Nazareth, but Bethlehem (necessary to fulfill the prophecy).
Of course, there are two possibilities: Jesus
was born in Bethlehem, and did fulfill the prophecy, because the prophecy was about him; or, this was written into the text, to attempt to convince a Jewish audience that had a hard time accepting that God’s Messiah would have been born in Nazareth, so far from Jerusalem (Galilee, as we know, was separated from Judea by Samaria!

). And we all know about those “godless” Samaritans
Thus, the motivation to have Jesus born in Bethlehem was clearly there, which doesn’t prove anything, per se, but does cast
reasonable doubt on the authenticity of the narrative.
But I certainly don’t mean to call the early Christians “morons” or “half-morons.” Obviously, they were quite intelligent.
only problem I’ve seen with regard to Joseph Smith is that there are no relics to be found for any of its history, centers of population, or battles. God did a wonderful clean-up job for them, didn’t He?
And yet thousands of people believe, some of whom – no doubt-- are above average in intelligence. You would think that Mormonism would have been immediately discredited, in a generation. Why wasn’t it? Today, there are about 6.1 million adherents.