At least that’s what they told the peasants. In reality it’s all about power politics and money. Same as now.
You gotta remember that for 2000 years the church was politics. Sure there were kings but who crowns the king? The church does.
Because Occam's razor is clear. I successfully grow flowers on my balcony and my verification and peer review of temperature is not alarming. It's hard to make a living as a scientist, and journals need sensationalism, so of course people in their 30s+ would show me numbers that fit the agenda. From logical thinking the deduction is there is no global warming, but I do believe there is in some parts of the world, and we'd best do something about it.
Same thing goes for what ancient civilisations believed within the concept of their lifestyles.
Much of the bible is a mix of history inspired folk tales, political propaganda, morality tales, and self-help advice from various eras. It’s a great resource in that respect, but I wouldn’t use it to explain any particular “how”
You get the holidays and culture, nice set of shared stories and a shared common sense. Thinking any of it is factually accurate or that god is a thing or being that actually exists is almost considered weird.
In Slovenia (where I’m from), for example, about 70% of the population identifies as Catholic, but only 25% say there might be a god. Another 30% say there’s probably some sort of greater spirit, but not necessarily god.
The American version always seemed odd to me. Believing that stuff in the Bible is factually true, not just fables with lessons ... that’s weird.