bjs1 is making an apologetic that has to be taken seriously.
'If you don't trust the Bible, how can you trust any other book?' Sometimes manifesting as 'prove that Julius Caesar/George Washington/Lincoln lived'.
The evaluation of historical record here is a tricky one. Many of them contain plainly mythical elements, or at least doubtful ones. When the Viking discovery of America was first suggested it was treated as a crackpot theory. Even when it was taken more seriously (more because people got used to the idea than there was any more evidence for it
) there was not much evidence. Only a few disputed stones claimed to have Norse runes on. Now the Viking settlements have been found and so that matter is 'settled'. The matter of historical figures is easier. We have a lot of evidence to support Washington, and even Caesar though I'm foggy about the amount of supporting evidence.
The existence of Pilate was never doubted though the never -mentioned worry was that Josephus and Philo didn't match in detail though they portrayed him in the same character. But the inscription found at Caesarea was the 'Viking settlement' of Pilate. And if he was real, that Jesus was, right? Well, arguable.
What isn't arguable is that there is no extra - Biblical evidence for Jesus as anything more than a religion that people followed. Significantly, Philo says nothing about him and neither does Josephus IF one is persuaded that the Flavian testament is a forgery, and few would now deny that at least some
of it has to be fraudulent. I also think the reference to James is a Christian gloss and Tacitus is only recounting the Christian claim, which in any case only reports the sort of death meted out to a failed zealot messiah who had a following even in Rome. Well...that was known because there was a 'Church' in Rome even before Paul wrote his letter to them.
So for me it's not so much about whether Jesus existed but if he did, can we trust what the Gospels say about him? That's where the test case of the Nativities come in. If they are demonstrably fictitious, then something else that looks equally discrepant is going to be doubted. The death of Judas is a good 2nd example and the resurrection accounts after that. So the question of the crowds that followed Jesus around trampling on each others' toes
is dubious simply because you'd expect him to get a mention in the histories of the time.
What I argue is that Gospel text analysis can show how the gospels were put together and edited. That's why it is important to understand that the Sermon was originally just to the disciples and not to the huge crowd, even though Luke dragged them into it. That's not to deny that the gospels all claim huge crowds, including Mark, but sometimes it is in contradictory contexts.
While the Bible apologist can weave it all together (the 'many other things' excuse to invent anything you like), gospel contradiction to extent of arguably being Fabrication (1) makes a lack of lack of 'clean hands' which becomes legitimate reason to doubt anything that looks a bit fishy, and the importing of huge crowds into the Sermon which (it seems) was (in the purported "Q" document) originally just to the disciples, makes this airy bussing in of a load of Extras to make a huge audience look historically questionable.
Which, together with the uncanny feeling that underneath the bold declarations of fame and a huge fanbase, Jesus' mission was actually small and secretive, might account for why Extra biblical historians know nothing about him, other than possibly Tacitus, who just says that Pilate crucified the one that 'Christians' were named for..
(1) e.g not a single parable in John and not a hint of John's sermon in the synopticss