Well, this is a rather strange statement. The 1962 Missal was obviously promulgated by John XXIII., but much of the liturgical reforms were done according to the recommendations of the commission set up by Pius XII. The latter Pontiff himself said that the reforms were far from being finished, even forbidding the printing of Breviaries which include his new rubrics.
The changes from the 1955 to the 1962 Missal are, in my view, not too big. I guess you are familiar with the new classification of feasts, the reduced number of feast-days and octaves and of course the adding of St. Joseph into the Canon as well as the abolishing of the second Confiteor.
Nothing against faith and morals there, as I see it.
Wikipedia gives a good summary of the
reform of Pope Pius XII. , feel free to compare it for yourself.