Nope. One must first have a religious faith/belief that ... John the Baptist, Jesus of Nazareth, and his brother James were real historical figures. It isn't wrong to do so, but it is a matter of faith, not any sort of objective truth. There is otherwise no independent historical accounts of either John the Baptist, Jesus of Nazareth/Galilee/Bethlehem, and his brother James from the time period of their supposed lifetimes. There are only a paltry few references to biblical characters well after (decades) those biblical characters were written, which was well after (decades) their supposed lifetimes.
Hence the faith requirement.
The problem with militant atheists and holy roller literalists is they are dogmatic and extremely prone to confirmation bias in everything they read pertaining to religion.
The New Testament is not a true historical narrative, but nor is it a complete fabrication of people and events.
Chronology of Written Sources: It's incorrect to confidently say nothing was written about NT characters until decades after they were gone.
Paul's authentic epistles, and the author of Mark were writing when the apostles Peter and James were still around.
Luke specifically writes that many people were recording the stories of Jesus and his disciples before him, but those written sources didn't survive. What we have now is what survived. But there were earlier written sources that have been lost to time.
By ancient standards, sources that post date the actual events by decades is about as good as it's going to get. Herodotus was writing about the Greco-Persian wars about six decades after they occured. And those are our best sources on the Greco-Persian war.
Non-Christian sources: The preeminent first century Jewish historian Josephus records the historicity of Pontius Pilate, Jesus, John the Baptist, Jesus' brother James the Just, and the high priest who oversaw Jesus' trial, Joseph, son of Caiaphas. Most scholars consider these historical references authentic, even if they have been reworked by Christian scribes.
Archeological Evidence: A tablet bearing the name of governor Pontius Pilate was discovered mid 20th century. The ossuary of the high priest Joseph, son of Caiaphas seems to have been identified. And while it is still open to debate the ossuary of James the Just, brother of Jesus, seems to have been found.
Now, start frantically Googling IBDumbass.
