Christianity isn't fixated on ancient Israelite culture, Christianity is fixated on the history of God's dealings with his people.
You won't find in the Bible:
- Ancient Israelite sports
- Ancient Israelite childrens' games
- Ancient Israelite recipes
- Ancient Israelite fashion
- Ancient Israelite hair and makeup styling
- Ancient Israelite marriage rituals or liturgies
- Ancient Israelite economic theory
- The expectation that anyone adopt any aspect of Ancient Israelite culture except their worship of the true God
When you do see Ancient Israelite culture discussed, it's usually discussed only in passing, incidental details that we often now can't properly understand. The Ancient Israelites didn't need to write about their culture - they knew it! They needed to write, read, speak, and hear the words of God, which no one can know except by God revealing himself to them.
What you do find in the Bible is:
- How God created the world and humanity
- How humanity sinned and became separate from God
- How God condescended to forgive and dwell with sinful people
- How God prepared his people to understand his plan of salvation by,
- How he taught his people the seriousness of sin by instructing them to enact symbolic rituals in the sacrificial system
- How he taught his people of his great holiness by demanding that even while he lived amongst them, that none could approach his presence except the High Priest, once a year, and after an expensive and bloody animal sacrifice
- How he taught them that knowing what is right is not enough to overcome a human's tendency to sin
- How God showed his patience and persistence as he repeatedly forgave Israel for their unfaithfulness to him as they worshipped false idols
- How the ultimate solution to our problem cannot be found in sacrifices and the attempts to appease God by our own efforts, but only through God securing our salvation through the death of the Son of God, Jesus, and through our transformation as the Holy Spirit dwells within us
Without the theological history of Israel the cross doesn't make sense. It's not at all obvious that the wisest plan God could make is to send his only son to the earth as a human, to be abused by his people, and then to be killed by one of the most painful methods of execution humanity has ever invented.
It makes sense because the history of Israel shows us that promises, covenants, rituals, laws, sacrifices, temples, priests, theocratic rulers, and even God-appointed kings can't permanently solve the problem of sin's corruption of the human heart. God prepared Israel, and us, to understand and accept the cross through trying every alternative we could think of.