These are Jewish books that were never inspired.
That's the opinion of later Jewish authorities when the Jewish Canon was being settled in the 2nd and 3rd centuries by the rabbinic authorities, and it's also the general opinion of most Protestants.
I think a more honest assessment is simply that the Deuterocanonical texts have both a long history of acceptance in the Church, as well as a history of being called into question.
There simply isn't a definitive and authoritative answer to whether or not the Deuterocanonicals are Canon or not. There are definitive and authoritative answers for some Christians, based on their own church's tradition on the matter, for example the Council of Trent in Catholicism, and the various Protestant Confessional texts of different Protestant bodies over the last five hundred years. But there has never been anything resembling a broad, definitive, consensus on the subject in Christianity that can be agreed upon by most everyone.
Granted, I'm also a Lutheran, and Lutheranism doesn't have a definitive position on this subject--the question is open precisely because there is no definitive and authoritative answer to the subject from our perspective. Yes, Luther himself did not consider the Deuterocanonicals to be properly Canonical Scripture (though still important and ought to be read in the Church), but Luther's opinions don't define Lutheranism. As such, since I view the question is technically open, I think dogmatic responses on either side as saying far more than one can actually say. The most honest answer is simply that whether or not the Deuterocanonicals are Canonical Scripture or not remains an open-ended question with which there are significant disagreements within Christianity, and without something definitive that we can all agree upon the issue will remain open in the foreseeable future.
For every ancient father of the Church who does not include [some or all] of the Deuterocanonicals in their Canon lists, there are fathers who do. Which, again, leaves the issue open-ended since there is no firm, universal agreement among the fathers here that we can point to here. St. Athanasius, for example, does not include most of the Deuterocanonicals, but does include Baruch, while excluding Esther. St. Jerome took issue with the Deuterocanonicals, at least initially, but did ultimately include them in his translation of Scripture in Latin (the Vulgate). The local councils at Carthage and Hippo affirm all of the Deuterocanonicals that would eventually be accepted at Trent hundreds of years later, though other local councils such as the one in Laodicea while accepting them have some disagreements with those western local councils. As such, we see differences and disagreements on such matters both when looking at the fathers themselves, and the local pronouncements of different geographic areas of the ancient Church. All of which makes the issue far from crystal in its clarity.
And if none of those things matter, and if one wants to play the "All of the Old Testament is quoted in the New Testament and that's how we know it is Scripture" then it's worth noting that this simply isn't true, there are a number of books which are never quoted, or even alluded to, such as Esther, the Song of Songs, Nahum, and Lamentations. So as a metric of canonical status this simply doesn't work, at least in and of itself.
The simple fact of the matter is that canonicity is something that came about by general consensus in the Christian Church, there simply isn't some divinely inspired table of contents to be found in the Bible itself, nor is there an ancient ecumenical council which enumerates the number and names of the canonical books. The Bible exists because of how it has been received, transmitted, and confessed over time, by the general consensus of the Christian Faithful, throughout history until the present day--and there are still matters, such as the status of the Deuterocanonicals, which simply have never been fully settled.
-CryptoLutheran
