Hail Mary is actually straight out of the Bible
She is the Mother of all Christians and the Queen of Heaven. Saint St. John of Shanghai and San Francisco sums it up best: All who hated Jesus Christ and did not believe in Him, who did not understand His teaching, or to be more precise, did not wish to understand as the Church understood, who wished to replace the preaching of Christ with their own human reasonings -all of these transferred their hatred for Christ, for the Gospel and the Church, to the Most Pure Virgin Mary. They wished to belittle the Mother, so as thereby to distroy faith also in Her Son, to create a false picture of Her among men in order to have the opportunity to rebuild the whole Christian teaching on a different foundation. In the womb of Mary, God and man were joined. She was the One Who served as the ladder for the Son of God, Who descended from heaven. To strike a blow at Her veneration means to strike Christianity at the root, to destroy it in its very foundation.