O ye atheists who do not believe in ?God, what fools you are ! But if you do believe there is a God, you must also believe there is a true religion. And if not the Roman Catholic, which is it? Perhaps that of the pagans who admit many gods, thus they deny them all. Perhaps that of Mohammed, a religion invented by an impostor and framed for beasts rather than humans. Perhaps that of the Jews who had the true faith at one time but, because they rejected their redeemer, lost their faith, their country, their everything. Perhaps that of the heretics who, separating themselves from our Church, have confused all revealed dogmas in such a way that the belief of one heretic is contrary to that of his neighbor. O holy faith! Enlighten all those poor blind creatures who run to eternal perdition! (St. Alphonsus Liguori)
Indeed. I never said otherwise. Those Orthodox who harden in their desire for separation put their souls in grave danger. So do many nominal Catholics who deny what their Church teaches.