The reason is because those texts are much older, and that was the style of religion practiced back then. Most God stories and stories about Gods in that period were like it. Most city states and tribal states had their own Gods that reflected them, and conflicts were gravely exaggerated. Also literally everything that happened in that state were an attribute or reflection of that particular God. With stories of how that attribute came to be, which reflected back in the people and in that way religion was a complex social interaction.

The people who wrote the stories we now know as the old Testament didnt write them as a part of a bible. These were stories of people who were taken out of their states and captured. Forced to live outside their land, but they took their God with them. Who became this omnipresent God that would lead people back to a promised land. Including all the complex social interaction people had with their mostly oral religious stories and traditions.

And it’s the continued tradition that lead to the formation of religious scholarship and the idea that Gods could be of the earth and not just of a state. Which brought about new thoughts, new traditions, new religious complexity written down in the New Testament. Which lead to the desire to make religious books encapsulating all of religious thought.

And only much later came literalism, the mistake to take everything in the Bible literal. which sparked the formation of atheism as we know it today.