The Marian doctrines are discussed because they are so clearly non biblical and obviously novel ideas not heard of until many hundreds of years after the resurrection.
Many hundreds? Not true; the early Church fathers refer to the Marian doctrines as old, settled doctrine. Already by only 130 years after Christ’s resurrection, she is universally acknowledged as the Mother of God (Theotokos, or “God bearer”) and no true disciple would argue that.
St. Justin Martyr (ca AD 155, Dialogue with Typho the Jew)
Identifies Mary as the new Eve, because Eve “conceived the word of the serpent, and bore disobedience and death” but Mary “received faith and joy” and bore for us our Savior in obedience to God.
St. Irenaeus (Against Heresies, inter AD 180-199)
Again referring to Mary as the new Eve:
“Thus, the knot of Eve’s disobedience was loosed by the obedience of Mary. What the virgin Eve had bound in unbelief, the Virgin Mary had loosed through faith.”
“The Virgin Mary… being obedient to His word, received from an angel the glad tidings that she would bear God.”
Tertullian (The Flesh of Christ, inter AD 208-212)
“… why is Christ called Adam by the Apostle?.. God recovered His image and likeness in a procedure similar to that in which He had been robbed of it by the devil. … Likewise, through a Virgin, the Word of God was introduced to set up a structure of life. … Eve had believed the serpent; Mary believed Gabriel. That which one destroyed by believing, the other, by believing, set straight.”
Even before the early Church fathers, Mary is in the book of Revelation: “a woman clothed with the sun, with the moon under her feet, and on her head a crown of twelve stars” in childbirth with a son. His name is not directly mentioned, but it is obvious that the child is Christ, so the woman is Mary. The dragon fighting her is clearly identified as Satan (Rev 12:9).
Do you want to stand with the dragon or with the woman?