There are Bible passages where Jesus makes it very clear that we are not to assign any special veneration/worship/adoration to his mother.
Further, I have seen no postings which deny Mary was blessed.
Luke 1:41-43 in my Protestant, King James Bible reads:
...when Elizabeth heard the salutation of Mary, the babe leaped in her womb; and Elizabeth was filled with the Holy Ghost:
And she spake out with a loud voice, and said, Blessed art thou among women, and blessed is the fruit of thy womb.
And whence is this to me, that the mother of my Lord should come to me? Luke tells us that the Holy Spirit caused Elizabeth, with a loud voice to venerate Mary. If someone wants to argue that the spoken words of Christ should be heard to contradict the spoken words of the Holy Spirit, I think that person has a pretty strong burden of persuasion.