Now I am confused. Are you saying that a Protestant cannot subscribe to traditional Catholic Marian beliefs? Were Martin Luther, John Calvin and John Wesley Protestants or Catholics? Are present-day Lutherans Protestants or are they Catholic?
You are not confused. You're just being argumentative and yes, I will repeat - PROTESTANTS can NOT embrace Catholicism's teachings concerning Mary. She is NOT our co-mediatrix. She is NOT the co-Redeemer. She was NOT sinless. She was NOT assumed into Heaven. Many of these Marian doctrines come from visions of "Mary" herself. They preach a different Gospel. And therefore, No, Luther or Calvin could not embrace them. Wesley was an Anglican. I doubt seriously that he would have embraced Marian theology as it current stands in the Catholic church either. As to what Modern day Lutherans are, some I would venture to say aren't even Christian in the Lutheran sense of understanding. The same could be said of modern Episcopalians, Methodists, Baptists, Catholics and all churches. You have very few Lutherans who follow Luther's teaching to the tee. In some ways, this is actually a good thing, because even Luther was a product of where he came from and wasn't entirely consistent at all times with his beliefs.