Personally I have no objections to the Immaculate Conception, for reasons I could go into. I think it's an unfortunate reaction against Catholicism that comes from bitterness, not historical theology.
Would you mind talking about it a bit? I would understand fully if you'd rather not.
I view the Immaculate Conception as a legitimate theological opinion that is consistent with the Church’s understanding of Mary and her role in salvation. Orthodoxy affirms, among other things, the following:
Mary’s role in salvation was revealed as early as the Fall (“I will put enmity between you and the woman…”)
Mary’s conception was miraculous and is celebrated as a feast day
Mary was dedicated to God by Joachim and Anna in thanksgiving for her birth
Mary is the Mother of God because she gave birth to Jesus who is fully God and man
Mary was “full of grace”, which the Greek word indicates as a continuing state of being as a result of a past action
Mary was betrothed to Joseph, who was her caretaker, but did not have sexual relations with him, remaining a virgin throughout her life
Mary was holy, pure, and blameless throughout her entire life
Mary was taken into heaven, body and soul, after her death
Mary is the Queen of Heaven by virtue of being the mother Christ, the King
Mary is our greatest human intercessor, whose prayers have assisted countless people, as revealed to many of the saints of the Church
If all this is true, then how would it be incorrect to extrapolate that Mary’s holiness began at conception? While Orthodoxy doesn’t define original sin in the same way as the west, we would agree that it includes a corruption of our nature, which includes our reason, ability to make moral choices, and a propensity toward sin. Mary could not have shared in that corruption if she was to live a life of perfect holiness as we say that she did. This doesn’t mean that she didn’t struggle against temptation, experience physical suffering, or die, since Christ himself experienced all those things. While conceived good, she was capable of further growth in holiness just as we all are, even after the end of our earthly lives. This also doesn’t mean that she lacked free will to choose good over evil, since Adam had this capability before the fall. It seems ridiculous to me to make a dogmatic stand against this idea when the overwhelming amount of our understanding of Mary is consistent with it.