Animal sacrifice was not God's idea. It was a practice that was already taken place in many parts of the world, and it has pagan origins. There is evidence that it originated in Egypt.
The Israelites, when they came out of Egypt, wanted to continue eating flesh. Remember that God gave them manna, but they complained and angered God? And I'm sure you remember the passage about how God gave them what they wanted, until it came out of their nostrils.... and then He struck them down with a severe plague and they died. The place where they died, Kibroth Hattaavah, literally means "The grave of craving."
Before I get to what you said, please read the following verses. Please don't skim over them, but really read them:
Hosea 6:6
For I desire mercy and not sacrifice,
And the knowledge of God more than burnt offerings.
Jeremiah 7:22-24
For I did not speak to your fathers or command them in the day that I brought them out of the land of Egypt, concerning burnt offerings or sacrifices. But this is what I commanded them, saying, ‘Obey My voice and I will be your God, and you shall be My people. And walk in all the ways that I have commanded you, that it may be well with you.’ Yet they did not obey or incline their ear, but followed the counsels and the dictates of their evil hearts, and went backward and not forward.
Psalm 40:6
Sacrifice and offering You did not desire;
My ears You have opened.
Burnt offering and sin offering You did not require.
Psalm 51:16-17
For You do not desire sacrifice, or else I would give it;
You do not delight in burnt offering.
The sacrifices of God are a broken spirit,
A broken and a contrite heart—
These, O God, You will not despise.
Proverbs 21:3
To do righteousness and justice
Is more acceptable to the Lord than sacrifice.
1 Samuel 15:22
But Samuel replied:
“Does the Lord delight in burnt offerings and sacrifices
as much as in obeying the Lord?
To obey is better than sacrifice,
and to heed is better than the fat of rams.
Isaiah 1:11-17
“To what purpose is the multitude of your sacrifices to Me?”
Says the Lord.
“I have had enough of burnt offerings of rams
And the fat of fed cattle.
I do not delight in the blood of bulls,
Or of lambs or goats.
“When you come to appear before Me,
Who has required this from your hand,
To trample My courts?
Bring no more futile sacrifices;
Incense is an abomination to Me.
The New Moons, the Sabbaths, and the calling of assemblies—
I cannot endure iniquity and the sacred meeting.
Your New Moons and your appointed feasts
My soul hates;
They are a trouble to Me,
I am weary of bearing them.
When you spread out your hands,
I will hide My eyes from you;
Even though you make many prayers,
I will not hear.
Your hands are full of blood.
“Wash yourselves, make yourselves clean;
Put away the evil of your doings from before My eyes.
Cease to do evil,
Learn to do good;
Seek justice,
Rebuke the oppressor;
Defend the fatherless,
Plead for the widow.
Micah 6:8
He has shown you, O man, what is good;
And what does the Lord require of you
But to do justly,
To love mercy,
And to walk humbly with your God?
So as you can see, God wants MERCY, not sacrifice. Now getting to what you said, there are a couple different views on animal sacrifices, from a Christian vegan perspective.
One view is that since animal sacrifices were already taking place, but were being offered to false gods, God "met us where we're at" with the intent of weaning His people off of animal sacrifice. He did that in two parts. The first part was to stop people from offering sacrifices to false gods. And to set up specific rules about what was already taking place. (Similar to what was done with slavery...which is also not what God wanted in the first place.)
And the second part was to end animal sacrifice altogether, through the once and for all sacrifice of Jesus who offered Himself, as the spotless Lamb of God.
Jesus sacrifice was supposed to put an end to all animal sacrifice. But of course mankind is selfish and continues to do what they want to do.
Another view, which is much more controversial, is that as it states in Jeremiah the "lying scribes" changed and added to God's word, because they simply wanted to continue sacrificing animals. Not only because they wanted to eat flesh, but because the animal sacrifice system was hugely profitable.
In fact, I created a thread yesterday that touched on that topic. You can read it here, if you haven't already:
One of the few times Jesus displayed righteous anger was when He famously turned over the tables in the Temple, an incident written about in all the Gospels... Also known as the Cleansing of the Temple.
Here's the passage, in Matthew 21:
And Jesus entered the temple area and drove out all those who were selling and buying on the temple grounds, and He overturned the tables of the money changers and the seats of those who were selling doves. 13 And He *said to them, “It is written: ‘My house will be called a house of prayer’; but you are making it a den of robbers.”
When Jesus...
There's more to be said about this, but once again this is getting lengthy. Maybe
Carl in Michigan can chime in, but I will try to come back later.