I see what you are saying in that people can try to understand things different ways or give them a different understanding than what may have been intended. However, words can and do communicate the author’s intentions, and in order to gain an understanding of what the Church has always meant by a particular teaching, we must first start with her most authoritative sources and read them
in their full context. What so often seems to happen regarding no salvation outside the Church is people will try to read the old documents intent on getting them to mean something different than what they clearly say and they will even try to divorce individual dogmatic statements and definitions from the rest of the explanations given along with them in order to try to change their meanings.
If I tell you that outside of Noah’s ark,
no one at all survived the flood and that only those inside the ark were saved, would you then try to interpret my statement to mean that possibly there were some people that were not in the ark but that were still saved? That obviously would be ridiculous because I already ruled out this possibility when I used the words “no one at all.” Had I simply said that people needed the ark in order to be saved, then you could conclude that possibly people could have hung on to the ark or had life boats attached or strings to other boats or possibly that by seeing the ark it gave them hope and then they were able to be saved from the flood by mustering up extra strength to stay above water and hold onto wreckage, etc. When the wording is vague, people can draw different meanings, but when the wording is clear and says “no one at all”–especially in a dogmatic definition–we can know for certain that the Church meant “no one at all.” If she meant “no one except…” then she would have lied when she said “no one at all.”
IV Lateran Council 1215: “One indeed is the universal Church of the Faithful, outside of which
no one at all is saved.” Pope Innocent III ex Cathedra.
fordham.edu/halsall/basis/lateran4.html
The Council of Florence (A.D. 1438-1445) From Cantate Domino — Papal Bull of Pope Eugene IV:
(Infallible General Council & Ex Cathedra papal declaration)
ewtn.com/library/COUNCILS/FLORENCE.HTM
The sacrosanct Roman Church…
firmly believes, professes, and proclaims that those not living within the Catholic Church, not only pagans, but also Jews and heretics and schismatics cannot become participants in eternal life, but will depart “into everlasting fire which was prepared for the devil and his angels” [Matt. 25:41], unless before the end of life the same have been added to the flock; and that the unity of the ecclesiastical body is so strong that only to those remaining in it are the sacraments of the Church of benefit for salvation, and do fastings, almsgiving, and other functions of piety and exercises of Christian service produce eternal reward, and that
no one, whatever almsgiving he has practiced, even if he has shed blood for the name of Christ, can be saved, unless he has remained in the bosom and unity of the Catholic Church.
Council of Trent, Profession of Tridentine Faith
I do, at this present, freely profess and truly hold this true Catholic faith, without which
no one can be saved; and I promise most constantly to retain and confess the same entire and inviolate, with God’s assistance, to the end of my life.
uoregon.edu/~sshoemak/323/texts/trent.htm
Pope Innocent III. Profession of Faith Prescribed for Durand of Osca and His Waldensian Companions* [From the letter “Fitts exemplo” to the Archbishop of Terraco, Dec. 18, 1208]:
By the heart we believe and by the mouth we confess the one Church, not of heretics but the Holy Roman, Catholic, and Apostolic (Church) outside which we believe that
no one is saved (Denzinger 423).
catecheticsonline.com/SourcesofDogma5.php
Pope Pius IX, Allocution, Singular quadem. Dec. 9, 1854:
For, it must be held by faith that outside the Apostolic Roman Church,
no one can be saved; that this is the
only ark of salvation**; that he who shall not have entered therein will perish in the flood**
catecheticsonline.com/SourcesofDogma17.php
CATECHISM OF POPE SAINT PIUS X
27 Q. Can one be saved outside the Catholic, Apostolic and Roman Church?
A. No,
no one can be saved outside the Catholic, Apostolic Roman Church, just as no one could be saved from the flood outside the Ark of Noah, which was a figure of the Church.
ewtn.com/library/CATECHSM/PIUSXCAT.htm