This is a quick response to this comment.

The RCC and Orthodox positions on matrimony do vary to a degree that matters. Although they do have the same 7 sacraments and agreed upon apostolic succession… [..] The last true ecumenical council occurred in 787 AD, 267 years before the great schism. A full 730 years before the 95 theses. Therefore, Protestants, sola scriptura and all the rest of it simply did not exist and that movement was in direct confrontation to the RCC.
— The Eye of Sauron @ Sigma Frame “Cathodoxy’s Sacramental Marriage Construct”

The fundamental axiom of Roman Catholicism—which originated in the late 4th century—is:

The recent explicates the older^[1]

This axiom is doing a lot of heavy lifting in the comment above. Roman Catholicism and Orthodoxy look to themselves (the recent) to explain what came before (the older) and in doing so err regarding nature of their origins in the late 4th century. The first great schism was that prophesied by scripture in the rise of the Beast of Revelation.

You can’t trust a false church to tell you which schisms are real and which are not, nor which councils are legitimate, nor anything about apostolic succession or sacraments. You can only trust scripture. That is what sola scriptura means. By the testimony of the apostles and early church writers, treating scripture as the exclusive word of God is older than both Roman Catholicism and Orthodoxy.^[2]

Therefore, from Orthodoxy’s perspective, all of what happens in a Protestant church is a novel innovation in a faith tradition that split from a totally different church.

Roman Catholicism and Orthodoxy like to make the claim they they are the oldest iteration of Christianity and that Protestantism is the newest kid on the block. This is not an historically valid claim. The novelty was Roman Catholicism in the late 4th century, and like all subsequent Roman Catholic (and Orthodox) heresies, it was accompanied by protestants who protested against those doctrinal innovations. Orthodoxy, for whatever merits it might be owed in throwing off some of Rome’s innovations, still embraces the Beast’s image and mark.

So why the contempt for the axiom of sola scriptura? Because it stands in contrast to the fundamental axiom of Roman Catholicism and Orthodoxy. Both axioms, being axioms, are epistemologically equivalent. Their difference is where they place their faith: one in the Word of God and the other in the traditions of a denomination.

Footnotes

^[1] Others have described this as sola ecclesia (the church alone): the church citing its own current authority to explicate what came before it.

^[2] Kauffman & Zins, “A Gospel Contrary, First Edition.” p.17-67