It's a sin against Ecumenism to do this, Xavier
Nice one!

From failing to commit these "sins against Ecumenism", deliver us, O Lord.
That we may always "sin against Ecumenism", we beseech Thee, O Lord.

Btw, Ecumenism is only supposed to be among baptized Christians who believe in (and have been baptized into) the Trinity according to Unitatis Redeintegratio. In pre Vatican II documents like a Holy Office directive under Pope Pius XII, it is said even of them, "It should be made clear to them that, in returning to the Church, they will lose nothing of that good which by the grace of God has hitherto been implanted in them, but that it will rather be supplemented and completed by their return. However, one should not speak of this in such a way that they will imagine that in returning to the Church they are bringing to it something substantial which it has hitherto lacked. It will be necessary to say these things clearly and openly, first because it is the truth that they themselves are seeking, and moreover because outside the truth no true union can ever be attained" which is clear and perfect.
"The missionaries of the 16th century were convinced that the unbaptized person is lost forever. After the [Second Vatican] Council, this conviction was definitely abandoned. The result was a two-sided, deep crisis. Without this attentiveness to the salvation, the Faith loses its foundation.
https://catholicism.org/pope-emeritus-speaks-on-necessity-of-baptism-and-no-salvation-outside-the-church.html"Pope Benedict asks the piercing question that arose after this palpable change of attitude of the Church: “Why should you try to convince the people to accept the Christian faith when they can be saved even without it?” As to the other consequences of this new attitude in the Church, the Catholics themselves, in Benedict’s eyes, are less attached to their Faith: If there are those who can save their souls with other means, “why should the the Christian be bound to the necessity of the Christian Faith and its morality?” asked the pope. And he concludes: “But if Faith and Salvation are not any more interdependent, even Faith becomes less motivating.”
"The Second Vatican Council has not been treated as a part of the entire living Tradition of the Church, but as an end of Tradition, a new start from zero. The truth is that this particular council defined no dogma at all, and deliberately chose to remain on a modest level, as a merely pastoral council; and yet many treat it as though it had made itself into a sort of superdogma which takes away the importance of all the rest."
Cardinal Joseph Ratzinger, now Pope Benedict XVI
given July 13, 1988, in Santiago, Chile
While people still argue over what Vatican II and the CCC say and do not say about EENS, it is clear traditionally people are not saved without faith in Christ, knowledge and love of Him as true God, contrition for one's sins, especially if one rejected the Truth, and desire for Baptism.
Outside the Church there is no salvation"
846 How are we to understand this affirmation, often repeated by the Church Fathers?335 Re-formulated positively, it means that all salvation comes from Christ the Head through the Church which is his Body:
Basing itself on Scripture and Tradition, the Council teaches that the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and Baptism, and thereby affirmed at the same time the necessity of the Church which men enter through Baptism as through a door. Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.336
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.337
848 "Although in ways known to himself God can lead those who, through no fault of their own, are ignorant of the Gospel, to that faith without which it is impossible to please him, the Church still has the obligation and also the sacred right to evangelize all men."338
Mission - a requirement of the Church's catholicity
849 The missionary mandate. "Having been divinely sent to the nations that she might be 'the universal sacrament of salvation,' the Church, in obedience to the command of her founder and because it is demanded by her own essential universality, strives to preach the Gospel to all men":339 "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you; and Lo, I am with you always, until the close of the age."340