When you look at the reasons people of the day actually gave it becomes worse. They refer to miracles. Many miracles but one central one, the resurrection of Jesus. Why did they believe these stories? Don't rational people just know they are all false? The best they can come up with is that the previous generation believed them. That is a bit lame. People don't just accept what the previous generation believed. Didn't youth question their elders back then? Again, when you read what they wrote, it appears they did. St. Augustine's Confessions is a good example of a young man asking many of the same questions young people ask today. He certainly didn't just accept what his mother told him without thinking about it.
Beyond the fact that the "previous generation" explanation is lame it really does not explain anything. It just pushes the question back. Eventually you get back to the time of Jesus and the Apostles. That is when worlds collide. Of course the writings of scripture and any writings related to them are treated with massive skepticism. No reason is needed to assume wild conspiracy theories. I get that it is hard for atheist zealots to be be rational about such matters. Why should we believe these hyper-credulous people?
Except they were not hyper-credulous. The Hellenists we have already said were very rational. Exactly the kind of people who should never believe miracle stories. Then we have the Jews. They were huge religious conservatives. They were still following the writings of Moses. They were willing to die rather than let the Greeks or Romans mess with their religion. Then when Jesus came along they had him killed because they didn't like religious radicals. Many of his followers got the same treatment. So this picture of a hyper-credulous society is purely something modern people have asserted to get their theories to work. It does not fit the data at all.
So what we have is a mismatch. You have what we are assuming are false stories about Jesus and His miracles and the apostles and their miracles. Then you have those who clearly believed these stories were true. But how did one flip to the other. When did the first Christians get out of "make it up as you go along" mode and get into "guard the deposit of faith with your life" mode? That is never very clear. You can see why. As soon as you start to say when it happened and how it happened and who was involved then you have a ton of problems. So the strategy is to be non-specific. Just make vague assertions and maybe nobody will notice that your theory in incoherent.
|Caravaggio: Martyrdom of St. Peter|
Then they allowed that religion to exert a dominating power over society for thousands of years. You can assume they never really questioned it but there is a lot of evidence they did. Evangelism was constant because doubt was constant. People kept coming back to the faith. Not just the stupid people but many very bright minds. The kind of people who were capable of declaring that the emperor had no clothes. Anyway, looking at the history of the middle ages is another topic but it is another period of history that atheism cannot make sense of.
The problem is that atheism is a rather obvious religion. So obvious that it is hard to imagine that any serious thinker in history did not consider it. So it becomes hard to explain why humanity has had such a hard time arriving at such a simple and obvious truth. Why the greatest minds of human history rejected it. It is even harder when you read their writings and see how seriously they took these questions.