Yet the Church tells us that private revelation adds nothing to the deposit of faith so I do not understand your comment " just because one does not rise to the level of formal heresy by disregarding what the Church teaches does not mean it can be tossed aside lightly."
If one beleives public revelation and feels that they do not need anything else then private revelations are not necessary for them. That is not tossing them aside lightly, that is they play no role in their spirituality.
An the private revelation plays no role in thier being declared Blessed.
Sort of like slavery and the Civil War were not related. Yeah right. If they had not had the private revelation, undoubtedly nobody would know their names or their lives and sacrifices, and they would not be declared Blessed. They were not declared blessed because of the private revelation, but it played a role in bringing them to the attention of the world, and the Church, for scrutiny. Just keeping it real here.
Private revelation does not add to the Deposit of the Faith. It is usually given to bring people who have strayed back to that faith. Jesus did miracles for a reason - sometimes decent people need to ‘see’. Some private revelation is like that.
Consider that Fatima’s Miracle of the Sun, witnessed by some 70,000 people, is without question the greatest miracle witnessed by the masses since the time of Jesus and the Apostles. The vast number of witnesses rules out fraud. So it happened.
The question remains, “Why?” This miracle alone makes Fatima unique. The fact that so many Catholic and non-Catholic folks know about Fatima and its secret makes it unique. The fact that the pope was publicly shot on the feast of Fatima, and it was prophesied at Fatima, makes it unique. The fact that the pope publicly consecrated Russia to the Immaculate Heart of Mary as specifically requested at Fatima, and then Russian atheistic communism collapsed with virtually no shot being fired, as promised at Fatima, makes it unique.
In short, Fatima is unique. Of course it is not dogma, or doctrine, or part of the Deposit of the Faith.
The miracle was great. But a little known fact is that the miracle was going to be bigger (perhaps the Miracle of the Sun would have been seen by all of Europe, maybe even halting the war?) but God pulled back, (From what I remember in reading this, it was because of the way the 3 seers were being treated but not 100 percent sure on this point.)
Fatima can therefore serve as a great inspiration and reminder of the power of God, and the power of prayer, and of how much we can do when we cooperate with Him and we do as He asks.
Nobody has to believe it, but everybody should.
God bless you.