True. Good point, however the fact remains that Jesus didn't come to abolish the law, He came to fulfill. Which means Jesus Christ came as the ultimate sacrifice, so now through Him, we don't have to carry out OT ritual of sacrifice etc. When coming to the Father, we just come through the Jesus Christ. We should not do away with OT teaching, as a lot of it is still very valid, and relevent in a Christian's life.
Matthew 5:17
17"Don't misunderstand why I have come. I did not come to abolish the law of Moses or the writings of the prophets. No, I came to fulfill them.