Not at all. It depends entirely of the claim "7. Jerome calls anyone who claimed he rejected the canonicity of the Deuterocanonicals, “a fool and a slanderer.”
Is, or is not, that a false claim?
In the end, St. Jerome followed the “judgement of the Church” and included the Deueterocanicals that were listed in the “Western Church” in his Latin Vulgate Translation. So perhaps it is your context that is not in line with history. So, in the light of history, it is reasonable to believe that Jerome was defending the inclusion of the Deueterocanonicals in the Canon. Had he only included the stories in the quote you site, then your point may have more validity.
Totally irrelevant!
So a question to you, as a Unitarian, why do you even care as you reject the Christological Doctrines of the Catholic and Orthodox CHurch as well, and most Confessional Protestants as well, although there are some here that have some “wackadoo CHristological views” that frequent here.
Several responses come to mind, some of them not very polite.
Why do you care what my motivation is?
You are correct in that "...there are some here that have some “wackadoo CHristological views". That observation would include Catholics, Protestants, and others.
You may note my tag "I am a Biblical Unitarian". And no, I have no intention of explaining what that means to me.
OLD REGGIE:
I have no intention of caring for your explanation of what a Biblical Unitarian is, just for the record. The question still is why are you, a Unitarian, so interested in the question of the NT Canon and the Catholic Church’s view of the Canon, which has historical legitimacy over the Protestant one. My conjecture is that you are a lapsed Catholic and thus have an axe to grind, of course, my conjecture could be off but my Sicilian blood usually does not fail me when sensing where people are coming from and you appear to be a lapsed Catholic with an axe to grind. .
Now back to the point at and, ST. Jerome is accurate, if you understand the context. He did question them while he was working on his translation and studying under Jewish scholars who were pushing the “Hebrew only books”, or what we now know is, Books that were only in Hebrew that they [Jewish Scholars] at that time were aware of as the findings at Qumran show that the Jewish-Essenes group did in fact have Hebrew translations of most of the Deuterocanonicals.
Jerome questioned whether the Deuterocanonicals should be included. On that point we can say “Yes”. What he did not do given the Councils that occurred after the Synod in Rome in 382, which drew up the list of canonical books in Rome and that list was the 46 OT canon, including the 7 Deueterocanoncals [even the OP by Gamecock in footnote 4 admits as much], i.e the Councils of Hippo in 393 and Carthage in 397, was challenge the authority of the Catholic Church once those Councils had all been accepted by Rome, which was the case during the time of Pope Innocent I whose letter to the Bishops in Gaul circa 405 AD corresponds to the time of St. Jerome’s letter that you cited.
Thus, given the entire context of that period in the History of the Catholic Church, it is true that 1) Jerome at 1 point questioned whether the Deuterocanoncals were “Canon” and 2) Given the Decrees of by 405, 3 Different Synods/Councils, and Pope Innocent I’s confirming said Councils, Jerome in humility submitted to the authority of the Church and accepted the 7 Deuterocanonicals as “Canon” which leads to the fuller context of his letter to Rufinus, who at one time was a close friend and ally of St. Jerome but several Letters between the 2 men dated circa 395 to 402 clearly illustrate a breach between the 2 men.