Yet, properly understood, it is correct. Sola scriptura doesn't mean Scripture alone is our authority, as is commonly believed, but rather that Scripture is the ultimate and only infallible authority. That some have different or incorrect understandings of the Bible doesn’t mean sola scriptura is false, much less "an insidious and evil doctrine."
Gal 1:8 But
even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed.
Gal 1:9 As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed. (ESV)
What is the standard here? Apostolic authority? No. The Church? No. Angels? No. It's Scripture—that which was already taught, which no apostle could change. Paul could not come back and teach something different, nor could Peter or any of the other apostles. In other words, Paul and the rest of the apostles are held to the standard of Scripture--sola scriptura--as the final and infallible authority.
1Co 13:12 For now we see in a mirror dimly, but then face to face. Now I know in part; then I shall know fully, even as I have been fully known. (ESV)
Paul even admits that he doesn't see perfectly, that he sees as "in a mirror dimly." That would apply to Peter and the rest of the Apostles, which means that none of them can be an infallible authority; it means that no person, including every Pope and Patriarch, could be, ever.
Those are the nails in the coffin of any idea that the Catholic or Orthodox Churches, or the leaders of them, are the highest authorities or infallible authorities on Scripture. Scripture alone is the highest and only infallible authority to which all Church leaders are subject.