@LukeHill The short answer is actually in Trent Horn's article which I included, but I used the opportunity to expand on why public confession is psychologically and spiritually beneficial for a larger purpose.
@curiousdannii You'll want to check the councils around the time the vulgate was published, but I am not sure a council would have to state the obvious, since the accepted canon wasn't what was threatening the church; and councils were typically called to address issues that threatened the faith. (Vatican II is a bit of an anomaly).