Why kill animals?

A theological post this week. I was reading Cynthia Boureault's excellent book The Wisdom Jesus recently. At one point she was discussing Jesus' passion and death, and talks about how Jesus came to earth to enable us to be one with God. Atonement, in the sense of at-one-ment, not in the sense of paying our debt. And that was when I had an epiphany.
In the Hebrew Bible, there are many laws and regulations for animal sacrifice. It was an integral part of their faith and worship. But why? Why must humans kill animals? How does an animal's death undo the harm of sin? It doesn't. It is, I believe, a powerful illustration of the cost of at-one-ment.
Animals are killed to teach us that becoming holy is unsurvivable. To draw near to God, to be one with God, is to be consumed. Nothing can survive. We long to be with God, just as God longs to be with us, but we are too fragile. God's love would destroy us.
And that is what Jesus did for us: He created a bridge to God. By dying and coming back from the dead, He showed us that we can draw near to God. As we practice His life and incorporate His teachings, we increasingly gain the ability to draw ever closer to God. Holiness is now survivable.

I am not an evangelical Christian, and now I begin to understand why. Christianity is not about salvation. It is about wisdom. Jesus didn't come here to rescue me: He came to teach me. Just as I do not rescue my daughter, I teach her. I follow Christ in order to find at-one-ment with God.