Allow me to redeem my original focus from a previous thread I made concerning the Reformers rejection of the Apocryphal writings
1. Catholics and others call "them" (which ever of the ENDLESS number of sets you're talking about) as DEUTERO-canonical. The word "deutero" means secondary or under. Consider that.
2. The handful of denominations that SOMEHOW, to SOME level, in SOME way "embrace" SOME unique "set" of "them" do not agree at all about them. Every one of those denominations (several OOC ones, the EOC, the current RCC, the Anglicans, the Lutherans) all have DIFFERENT Deutero books and generally a different view and use of them. There is no consensus here. NEVER has been. Consider that.
3. For some 1400 years, the EOC and RCC had a different embrace of different DEUTERO books. Neither cared. It was never a debated subject. Why? Because they were seldom used and were considered as DEUTERO. And because both questioned their content and function. NO debate even though they had DIFFERENT Bibles.... because neither considered them significant or worth discussing much, much less debating. Consider that.
4. Actually, about HALF of Protestants DO accept "them" (again, which "set" are you talking about?). The "Protestants" you are talking about are CALVINISTS, which dominate in the USA but in few other nations. O Anglicans actually accept more DEUTERO books than the RCC Councils of Florance and Trent . Luther accepted one MORE than the RCC's Council of Florence or Trent did. Luther PERSONALLY held that these DEUTERO books be embraced as deutero but Lutherans choose to NOT make that position official or binding, Lutherans believed that an embrace or rejection of Books is something for the WHOLE church catholic to decided, not for one man or one denomination, and so Lutherans REFUSED to put a list in their confessions. But Anglicans DID do this - simply embracing a lot more of them than the RCC (or EOC for that matter). The comment about "Protestants" simply reveals an ignorance of by far the two largest Protestant faith communities in the world. Consider that.
5. This has nothing to do with the LXX. The RCC does not accept some of the material in the LXX either. The Jewish Council of Jamnia (90 AD) simply wasn't embraced by all Christians and some other books continued to be read by Christians which had been eliminated by the Jews. But they never "caught on" and remained controversal... and became typically known as "DEUTERO." The whole church has NEVER ruled on them - one way or the other. A FEW denominations have, but only since the 15th Century and only for that one singular, individual denomination, and NONE of them agree with ANY OTHER about this.... and none of them use them much. Lutherans are a bit of an exception here since Lutherans simply don't have the ego to appoint self to determine this matter. Luther INCLUDED the typical 16th Century GERMAN "set" in his German translation since Germans were use to them, but simply shared his PERSONAL OPINION that the DEUTERO books are deutero. Some others (the RCC, Anglicans, Calvinists, Mormons, etc.) have taken it upon itself to officially decided this - but this has been recent and no two denominations that embrace any DEUTERO book agree with any other on this. (Technically, the EOC and OOC are also like the Lutherans, not officially ruling). Consider that.
.