Thank you for your reply.
There is one very important aspect to our discussion that you are not considering. Your position and views don't take into consideration the suffering of innocent third parties, the animals, even though you acknowledge that they feel pain.
God said that He desires obedience and not sacrifice. Furthermore, the sacrificial system was never instituted until well after the flood, and only as a way of limiting the depravity of humans. And since nothing is mentioned about any reason for the shedding of blood, it is highly unlikely that God even considered it when providing coverings of skin for Adam and Eve.
Just as you originally read into Scripture that they killed an animal, so you are reading into Scripture about the need for the shedding of blood in this case.
We're not saying that you're not a Christian, because God sees the intent of the heart, unlike we humans can. Our main point is that God wants us to have a soft and repentant heart, and anything that hardens our heart separates us from God to some extent. As Ezekiel says, God wants to remove the heart of stone and give us a heart of flesh, that we would be obedient to Him. We don't want anyone to be separated from God by the things in their lives.
God's creation and heavenly intent has never changed. The rules that you say He changed, are simply concessions and methods of limiting the depravity of human beings until they return wholeheartedly to Him, which is exactly what Jesus was teaching us in the Sermon on the Mount. God wants us to return to his original intent. This is also what Paul wrote about in Romans 8:18-23.
All of this is intended to help us find ways of living that will remove the fallenness of creation from our lives to the best of our ability. We don't have to wait for Jesus to return to get this peaceable kingdom to begin to happen/return.
As a vet, you probably know that animals also have the same emotional feelings that we do. And the Bible teaches us that God created them as living souls, just as He created us.
We will never accept that people cannot change, because we know how much our lives changed, both in Christ and in his peaceful teachings.
In the Love of the Lord,
Frank and Mary