Pier Giorgio owes this title to one of his most well-known admirers: Pope Saint John Paul II. On March 27, 1977, then Cardinal Karol Wojtyla was asked to attend the opening of a Pier Giorgio Frassati exhibit in his diocese of Krakow, Poland. The exhibit was created for a youth conference being held by the Polish Dominicans.
Cardinal Wojtyla was filled with joy upon seeing the photos of the young man who inspired him as a student. He urged all those in attendance to take time to visit the exhibit saying: "Go and look at these photographs. Behold the man of the eight beatitudes who bears in himself the grace of the Gospel, the Good News, the joy of salvation offered to us by Christ..."
Later, back in Rome, Wanda Gawronska (Frassati's niece) was preparing another exhibit and was asked to provide a title. She remembered that Cardinal Wojtyla had called Pier Giorgio "the man of the eight beatitudes" earlier in Krakow so she suggested that title and it stuck. All of this happened years before Pier Giorgio was ever beatified.
In an unexpected turn of events, Cardinal Wojtyla became Pope John Paul II just a few months later and went on to beatify Pier Giorgio in 1990. During the beatification homily, as he had done in several other appearances, Pope John Paul II further solidified the connection between Blessed Frassati and his title of "Man of the Eight Beatitudes."
By his example he proclaims that a life lived in Christ's Spirit, the Spirit of the Beatitudes, is "blessed", and that only the person who becomes a "man or woman of the Beatitudes" can succeed in communicating love and peace to others. - Pope Saint John Paul II, May 20, 1990