This stuff is so silly it defies belief. After Vatican II what people believe no longer center on truth according to Notre Dame's Fr. McBrien, from The Tidings:
There were always Protestants attracted to the Catholic Church in the pre-Vatican II era for biblical, theological or historical reasons, all of which were carefully laid out in Father John O'Brien's writings. With the Second Vatican Council, however, and with the ecumenical movement which the council and the popes had endorsed, it became practically impossible to present the Catholic Church any longer as "the one, true Church" and all other denominations as awash in error and falsehoods.
And so the traditional apologetical tactics --- "demonstrating" that Catholicism alone is right, while Protestantism is completely wrong --- were generally abandoned. If Protestants became Catholics in the late 1960s or in the '70s and early '80s, it was mainly for family reasons, or because they intended to marry a Catholic, or because they had grown familiar and spiritually comfortable with Catholic worship.
In the past two-and-half decades, however, we have seen something of a reversion to the pre-Vatican II approach. Many seeking entrance into the Catholic Church today do so as an act of rejecting their Protestant past and of embracing "the truth" found only in Catholicism.