I believe the point is not to debate your post, overcomer, but to provide an example of how SDA arguments assume that Rome is defining this or that for all Christianity, so that defeating or seeming to defeat Rome's argument therefore defeats whatever principle or concept is under discussion. The point of the OP, if I understand him correctly, is that because SDAs or at least SDA doctrine doesn't seem to understand or take into account that Rome does not decide matters for the Eastern Orthodox or Oriental Orthodox (and never has), the arguments created by SDAs as in your post are built on faulty premises that do not actually address the theology of the early Christian Church in toto (meaning, the Greek and non-Greek churches of the Eastern Roman empire, and beyond in places like Ethiopia, India, and Persia), but only Rome in particular.
Likely that is his case. But in general Baptists also don't go running to the Pope to ask him what they should believe. However the Protestant Reformation "did take place" so also the schisms of Catholicism into varied/myriad groups. The SDA argument comes from Acts 20 and 2Thess 1 about a great apostasy predicted by the NT writers -- resulting in the "dark ages".
As concerns that particular post, for instance, the Immaculate Conception is not believed by Eastern Orthodox or Oriental Orthodox; it is strictly a Roman Catholic idea, built on Roman Catholic presuppositions and ideas of original sin inherited from Augustine of Hippo
Indeed it would be hard to find any denomination at all - that believes in the "Immaculate Conception". And of course - it is not in the Bible.
So arguing against the immaculate conception does not argue against the sinless human nature of Jesus Christ, because that's not how Jesus "got" His sinless human nature
Correct - the Bible does not say that Mary was sinless or that it takes a sinless mother to have a sinless baby - if that were true then Mary, her mother, her grand mother, every mother to Eve ... would need an unbroken line of sinless mothers to have the incarnation of Christ.
Once you admit you don't need such a line then Mary is as good a "starting point" as any for a sinful-nature fully human mother to have a sinless baby.
The point is that SDA apologetics are so narrowly focused against Rome in particular as to ignore the historical and present reality of other churches outside of her
Why not put that proposal to the test?
The book "The Great Controversy" covers the Christian age from the destruction of Jerusalem -- to the Dark Ages, and the Protestant Reformation, the Great Awakening, the 2nd coming, the Millennium, the New Heavens and New Earth.
Free - online.
Online Books: The Great Controversy
Now if what you are saying is true - then the only group that book knows about - is the Roman Catholic church.
Why not test that out? Take a look.
If on the other hand - your argument is that all the Protestant Churches were actually protesting the Eastern Orthodox church and not the Roman Catholic church -- well here is your place to make your alternate history known to us.
The Protestants were not protesting most of what SDAs protest.
The "protesting Catholics" -- such as Wycliffe, Jerome, Huss, Luther, Calvin were ... "Catholics" demanding that their own church get back to Bible basics - NT church basics, ... testing all doctrine an tradition against the Bible. SDAs do insist on
sola scriptura testing of all doctrine and tradition. But we do not do it from "within" the Catholic church as the early "protesting Catholics" were doing it.
The "protesting Catholics" were choosing the
Bible over veneration of saints, purgatory, the immaculate conception,
the sale indulgences, the claims to authority that the Pope was making at the time.
SDAs also object to CCC958 "
Communion with the DEAD" and Purgatory , the immaculate conception, the sale of indulgencesm, the entire system of indulgences, the claims to authority that the Pope was making etc.
We also oppose the formal
earthly priesthood, bowing down before images in church and promising to serve and venerate those they represent and many other things of that sort.
We prefer the sola scriptura model of Mark 7:61-3 and Acts 17:11
And of course there is the American form of the Protest including Roger Williams' focus on the separation of church and state in the form of granting
religious liberty. Freedom to
worship God according to the dictates of the conscience.
The SDA objection is not focused primarily on the corruption of Rome, but rather on various doctrines shared by most Protestants.
Certainly it is true that the SDA set of doctrines do not just focus on opposing errors unique to the RCC
Now a purist, puritanical form of Calvinism, which is basically what Calvin practiced in Geneva, is almost like Adventism with Sunday worship.
SDA doctrine rejects Calvinism
So I cannot criticize Calvinism for ignoring Orthodoxy, whereas Adventism appears to do so.
consider this
There is a somewhat me-centered view that other religions arise just because they don't like yours -- they simply get up on the wrong side of the bed and say "hey -- today we don't like Methodists... or Baptists, ... or this particular Orthodox church .... or that particular Catholic church".
In that somewhat mythical world you could argue for "someone else not to like" and give some reasons.
But 'in reality" most protestant groups came into being based on "sola scriptura" reasons - where this or that doctrine is found to be Bible based and then it is also found that the Bible specifically identifies key players in history that promote truth - or promote persecution and error.
So it is not at all of the form "hey we woke up today really miffed about such-and-such a denomination".