Please can you give a source for this.
I was actually reading it from my Beloved’s copy of the
Vulgate (ed. Roger Gryson. Stuttgart: Deutsche BibelGesellschaft, 1994).

When one studies seventh-century saints, one collects some interesting texts. I have, however, managed to locate some online translations of his prologues to the
books of Solomon and to
Jeremiah. The comment about the books of Solomon is at the end of the second paragraph; that about Baruch is near the end of the prologue.
While Jerome certainly did include these texts in his edition of the
Bible, his reference to the church’s treatment of the books of Solomon, “inter canonicas scripturas non recipit… legat ad aedificationem plebis, non ad auctoritatem ecclesiasticorum dogmatum confirmandam”, clearly represents a difference in their status. Similarly, when he says of Baruch, “qui apud Hebraeos nec legitur nec habetur, praetermisimus”, he is actually placing that text outside of the task which he had been given, which was that of collecting together the Holy Scriptures. While he did go on to include Baruch, in obedience to his patron, the church of Rome, his prologues also remained.
Further, I would suggest that the representation in the Wikipedia article of the passage from
Against Rufinus is less than accurate, and not only in its spelling of “sycopath” [sic] or in the fact that it lists the location of the passage as “11:33” rather than
2:33. Roman numerals are, after all, very hard to read.
“he stoutly defended the deuterocanonical portions of Daniel even though the Jews of his day did not”, says the Wikipedia article. In
Against Rufinus, in section
33, we find Jerome’s ‘stout’ defence:
“I wished to show what was the opinion upheld by the Jews… The churches choose to read Daniel in the version of Theodotion. What sin have I committed in following the judgment of the churches?.. when I repeat what the Jews say against the Story of Susanna and the Hymn of the Three Children, and the fables of Bel and the Dragon, which are not contained in the Hebrew Bible, the man who makes this a charge against me proves himself to be a fool and a slanderer; for I explained not what I thought but what they commonly say against us… I wonder that a man should read the version of Theodotion the heretic and judaizer, and should scorn that of a Christian”.
(My emphases.) Thus, Jerome ‘stoutly’ displaces blame for his actions. It is
the Jews who prefer the Hebrew; Jerome is merely mentioning their preference. This guards him against accusations of opposition to the churches. It is then
the churches who may, if they so choose, prefer the textual version of a ‘heretic and judaizer’ over the version from the Septuagint. This guards him against accusations of presenting a bad version of the text. Jerome is covering himself on both sides by displacing all responsibility onto others; he was not a silly man. Note also Jerome’s own representation of the preferability of the Hebrew in section 34.
The immediate cause of all of this discussion was
Jerome’s Prologue to Daniel: “iuxta Septuaginta interpretes … non legunt, utentes Theodotionis editione, et hoc cur acciderit nescio”. Jerome is at a loss to explain the behaviour of the churches, and is quite happy to express his bemusement to the world.
He is not obediently acknowledging the authority of the Church, singular and universal, but rather shaking his head in disbelief at the incomprehensibility of the churches, plural and idiosyncratic.
I would say that ostensibly the Reformers removed the deuteros from their canon for this reason, but in reality it was because of the doctrine contained within the deuteros. In particular, the doctrine contained in 2 Maccabees.
I dare say that they had some reason to look for a denunciation of these texts, and that Jerome’s agreement with the established canon of the Tanakh provided them with the -]excuse/-] reason which they sought.