[If many dont accept Papal Infallibility, then why did they become Catholic? Why didnt they stay Orthodox? ]
One has to read the history of the Unia and how and why it came into being. You can start off by reading the 33 Articles included in the 'Union of Brest' and ask yourself why it was necessary to get guarantees from the RCC that these articles would be guaranteed before any union could take place -
You can find the document at -http://www.ewtn.com/library/COUNCILS/TREATBR.HTM
And ask yourself why Articles such as 12, 13, 17, 22-25 were needed if this union was a result of a general desire for union with the RCC as claimed by some within that church and its sui juris appendage.
They had no other choice than to become one with the RCC or be labelled as Traitors in their own lands.
Over 400+ years have gone by since this union and the results have been a disasterfor their children who after all these years are still searching for an identity and are confused on exactly what they are or what they want to be. They don't want to be known as full fledged papal Catholics (which they are) but they don't want to be full fledged Orthodox either (which they aren't and haven't been since 1596). Some are being told and now think they are 'Orthodox In Communion With Rome' which shows just how much they comprehend regarding one's religious identity. As my grandmother used to say when asked why she returned to Orthodoxy -
'Dey are neider here nor dere. Dey neither fish nor foul'!
As far as the Immaculate Conception. The shortest and clearist definition of the Immaculate Conception from an Orthodox Catholic point of view is -
Immaculate Conception = A poor solution to a non existent problem.
Also the Ecumenical Patriarch gave an excellent response to the issue of the Immaculate Conception -
> In the interview that follows 30Days asks Bartholomew I, Ecumenic
> of Constantinople, to comment on the Immaculate Conception.
> Full text of interview at
> Interviewer: The Catholic Church this year celebrates the hundred
> fiftieth anniversary of the proclamation of the dogma of the
> Conception. How does the Eastern Christian and Byzantine Tradition
> the Conception of Mary and her full and immaculate holiness?
> Bartholomew I: The Catholic Church found that it needed to
institute a new
> dogma for Christendom about one thousand and eight hundred years
> appearance of the Christianity, because it had accepted a
> original sin - a mistaken one for us Orthodox - according to which
> sin passes on a moral stain or a legal responsibility to the
> Adam, instead of that recognized as correct by the Orthodox faith -
> according to which the sin transmitted through inheritance the
> caused by the separation of mankind from the uncreated grace of
> makes him live spiritually and in the flesh. Mankind shaped in the
> God, with the possibility and destiny of being like to God, by
> choosing love towards Him and obedience to his commandments, can
> the fall of Adam and Eve become friend of God according to
> God sanctifies them, as he sanctified many of the progenitors
> even if the accomplishment of their ransom from corruption, that
> salvation, was achieved after the incarnation of Christ and
> In consequence, according to the Orthodox faith, Mary the All-holy
> God was not conceived exempt from the corruption of original sin,
> God above of all things and obeyed his commandments, and thus was
> by God through Jesus Christ who incarnated himself of her. She
> like one of the faithful, and addressed herself to Him with a
> trust. Her holiness and purity were not blemished by the
> on to her by original sin as to every man, precisely because she
> in Christ like all the saints, sanctified above every saint.
> Her reinstatement in the condition prior to the Fall did not
> take place at the moment of her conception. We believe that it
> afterwards, as consequence of the progress in her of the action of
> uncreated divine grace through the visit of the Holy Spirit, which
> about the conception of the Lord within her, purifying her from
> As already said, original sin weighs on the descendants of Adam
and of Eve
> as corruption, and not as legal responsibility or moral stain. The
> brought hereditary corruption and not a hereditary legal
responsibility or a
> hereditary moral stain. In consequence the All-holy participated
> hereditary corruption, like all mankind, but with her love for God
> purity - understood as an imperturbable and unhesitating
dedication of her
> love to God alone - she succeeded, through the grace of God, in
> herself in Christ and making herself worthy of becoming the house
of God, as
> God wants all us human beings to become. Therefore we in the
> honor the All-holy Mother of God above all the saints, albeit we
> accept the new dogma of her Immaculate Conception. The non-
> this dogma in no way diminishes our love and veneration of the All-
> Mother of God.