It seems we agree that the bible makes the Jews out to be the bad guys. But.... the Christianity that really took off was Paul's 'gentile friendly' version rather than the more othodoxly Judaic version promoted within Israel.
You'll notice that the entire NT has a Jewish theme of warning to it. That is because the OT Mosaic Covenant they made with God was never kept. He sent prophets and teachers to them to warn them that if they did not turn from their apostacy He would bring judgment upon them.
“Behold, I am going to send you Elijah the prophet before the coming of the great and terrible day of the Lord.
Jesus told His disciples that John was the Elijah to come.
And if you are willing to accept it, John himself is Elijah who was to come.
John was the one calling in the desert, warning Israel to repent before the axe struck the tree and brought it down (Matthew 3:5-12
7 But when he saw many of the Pharisees and Sadducees coming for baptism, he said to them, “You brood of vipers, who warned you to flee from the wrath to come?
10 The axe is already laid at the root of the trees; therefore every tree that does not bear good fruit is cut down and thrown into the fire.
So, Israel sensed judgment was coming upon them. You can find the theme of soon coming judgment and warning throughout the NT.
I think Jews - especially Jews inside Israel - may have been sympathetic Jesus, but less so to Paul's reformulation. So the Paulines more or less gave up on converting Jews and focused on outsiders, hence in their version of history it was Romans good, Jews bad.
Paul built on Jesus' teaching and part of that teaching was the atonement. Paul explained what Jesus accomplished. No animal was sufficient to take away sin. An animal did not sin against God yet God permitted it as a covering for sin until a perfect Man could offer Himself in the place of an animal.
The animal represented the person and nation for God had said that the soul that sins would surely die. Thus, it was a substitutionary sacrifice until Jesus presented the sacrifice that could take away sin. The book of Hebrews, among others, conveys this message.
6 Now when these things have been so prepared, the priests are continually entering the outer tabernacle performing the divine worship, 7 but into the second, only the high priest enters once a year, not without taking blood, which he offers for himself and for the sins of the people committed in ignorance.
The animal sacrifices were a pattern of a greater truth, as is the whole OT worship system.
What is more, animal sacrifices had to be made every year on the Day of Atonement to cover the sins of the people (Israel) they had committed against God. But Jesus offered a far greater sacrifice and one that did not have to be repeated over and over again, thus, His sacrifice pleased God. His life was holy and His sacrifice paid the penalty (in substitution, just like the animal did in the OT) for the sins of the believer.
13 For if the blood of goats and bulls and the ashes of a heifer sprinkling those who have been defiled sanctify for the cleansing of the flesh, 14 how much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God?
As I said, the reason that animal sacrifice could not take away sin, only cover it until the covenant was abolished, was that it was not an animal that had sinned against God and destroyed the intimate relationship with God that Adam enjoyed in the Garden until the day sin was found in him.
Thus, Jesus, the Second Adam, restored that relationship by the merit of His life lived on behalf of the believer. So, one He [Jesus] had atoned for sin He sat down at the right hand of the Father in the greater sanctuary, the heavenly one. He also established a new covenant in His blood, just like God had made a covenant with Israel with blood. Throughout the NT we see the transition taking place between the Old Covenant and the New Covenant. AD 70 marks the completion of the Old Covenant in which God judged and removed it in place of the eternal covenant.