I come from a religious background, born and raised catholic, and even in our indoctrinating upbringing it was made clear that the new testament isn't eyewitness testimony. It's a written story of something someone said. Given the age of the material this is the best we're going to get, obviously, but it's not quite as clear cut as it might seem.
https://en.wikipedia.org/wiki/New_Testament
" They were written between approximately 70 and 100 AD, and were the end-products of a long process of development; all are anonymous, and almost certainly none are the work of eyewitnesses."
Just because it doesn't support your _preferred_ narrative doesn't undermine the fact that it's effectively the most trustworthy source on damn near any topic including that one.
Either way, I don't see a huge epistemological problem with a person believing these things. They might be believing wrong things but at least they do it for reasonable reasons.
You need to distinguish between epistemology and logic. It's much more important to get your epistemology correctly than your logic. It's ok to be wrong with your reasoning, you can still have an intelligent discussion. But talking to a person without epistemology is like talking to the wall. You're playing chess and he's playing checkers.
If the other person doesn't epistemologically need cause and effect relationships to believe in something, and it doesn't matter to him, I can't have an intelligent discussion. I can't reason without cause and effect, and if it doesn't matter to the other person it's completely hopeless.