Because the Vatican made a pact with the communists.
The Communists have been doing this kind of thing all along.
In Fr. Pfeiffer's Second Sunday of Advent sermon, he mentions the "Pax
Priests" of Hungary, whom the Communists gave full freedom to
practice their religion in every way, to say Mass, have Benediction,
provide the Sacraments, everything, only they were forbidden to speak
against Communism. Theirs was a false peace.
And then so too, at Vat.II it was not a new experiment. It was a
tried-and-true technique, whereby the Church could do whatever it
would, only NOT condemn error. And this was what John XXIII of
infalicitous memory did on October 11th, 1962: he said the Church
would no longer condemn error, but would rely instead on the
infinite mercy of God.
At that point, the Pope gave up the farm, basically.
He abjured the practice of Papal Infallibility, AND he put up a fence
by which the Holy Ghost would not cross, and would not protect the
Council from error.
All the consequences -- including the unclean spirit of Vatican II,
and the most conspicuous Balamand Agreement, or the Metz Pact,
which promised the Council would not condemn the greatest
threat to the Church in her history, Communism, if only Russian
Orthodox observers (who were in fact KGB agents) would be
present at the Council -- all flowed from that horrendous
beginning, like a foul stream from the mouth of the infernal
dragon of hell, as if it were the fulfillment of prophesy,
which it in fact was!
"And the serpent cast out of his mouth
after the woman, water as it were a river;
that he might cause her to be carried
away by the river... which the dragon cast
out of his mouth... And he opened his
mouth unto blasphemies against God, to
blaspheme his name, and his tabernacle,
and them that dwell in heaven"
(Apoc. xii. 15-16; xiii. 6). Read all about it in the Third Secret of Fatima, once, that is, it is released...