You are correct to question its authenticity, (word by word) I wonder also. However, I do feel whatever the third secret is; it certainly must be a warning about the Great Apostasy, notice the timeline, 1960, that should be a clue for sure.
Yes, the Church has known for many centuries now that the Great Apostasy would involve Rome. Back in 1000 AD, the people were almost certain that Christ would come very soon due to the corruption in Rome. Here it is 1000+ years later, and we are still awaiting the Second Coming.
This recently released secret letter of Lucia was probably rewritten many years after 1960 to deceive even the elect, and was a forgery according to what Fr. Kramer,. Fr. Gruner, and others have written. Looking at the pictures of Lucia as a child and as a young nun, and then comparing those pictures with the Lucia who recently died shows that they do not match. Lucia as the older nun has a distinctly different facial profile; her bony structure is very different. While soft tissue may change due to weight and age, bones cannot lie.
If the Vatican is responsible for destroying the holiness of the Mass with the Novus Ordo, nullifying all the sacramental rites including the ordination of priests and the consecration of bishops, switching nuns (and priests, bishops, and even popes), creating forgeries, murdering John Paul I, and having drug parties and sexual orgies in the Vatican, then this shows how far the corruption and apostasy have gone -- too far.
How would Lucia have known that Pius XII would die late in 1958 a little more than one year before 1960, the year when Lucia's secret was to be released by Rome? This would barely be enough time to elect John XXIII who ultimately refused to release that secret.
Looking forward to the Medjugorje apparitions, where the adult children still receive VISIONS ON DEMAND, can anyone accept any of the recent apparitions, including Fatima?
St. Catherine of Sienna warned us that we must learn to discern, but discernment can only be achieved through much prayer and fasting. She herself was deceived by the devil who is the great shapeshifter and who can appear as an angel of light, as the Blessed Virgin, or even as Christ.