I know this thread is a few months old, and I see that it departed from it’s original topic…but I wanted to mention this.
The OP linked to a 1879 publication by one of the La Salette visionaries, Melanie, who made several disturbing (and false) prophecies that she claimed the Blessed Virgin revealed to her when she was 14. As explained at
churchinhistory.org/pages/leaflets/melanie.htm, this publication, though originally approved by the bishop, was later condemned and actually added to the Index of Forbidden Books.
The original vision of La Salette is approved by the Church, and many popes, including Pope John Paul II, have had a devotion to Our Lady of La Salette.
Some of the other posters remarked that a vision, to be authentic, must produce holiness in the visionary. While that might be sufficient for your own devotion, that is not the criteria the Church uses. For at least two reasons: 1) it would be necessary to wait until the visionary died to approve the apparition, 2) the vision does not take away the free will of the visionary. If a visionary curses God the day before he dies, that does not invalidate the vision itself.
This of course is in relation to the question of Melanie, one of the two children who are said to have had the vision. In short, as years went by, she expected praise from people for having had a vision of Mary. When she didn’t receive this, her writings became anti-clerical and she wrote all sorts of absurd things, hence the publication the OP linked to.