I've heard it claimed by some folks who critizes this theory that it is; but Rod Dreher balks. [Hat tip: Andrew Sullivan.]
I believe Orthodox Christianity is the fullest expression of the true path to salvation, liberation or paradise. But I don’t agree that only Orthodox Christians will find their way to salvation. My view is that God may save anyone, but that if anyone is saved, it is through the death and resurrection of Jesus Christ, and through the mercy of God the Father, who, in his infinite wisdom and compassion, may choose to extend it to those who confessed Christ imperfectly, or who didn’t confess him at all. That, by the way, is the official teaching of the Catholic Church. It’s not the same thing as universalism, which holds that everyone will be saved, no matter what.
Dreher is a convert from Roman Catholicism to capital O Orthodox Christianity. It always helps to clarify terms. Note also that there are Trinitarian Universalists (like Benjamin Rush) who believed, indeed, everyone will be saved (eventually) no matter what, but it will be through Christ's universal (as opposed to limited) atonement.
Finally, Dreher's link interestingly shows a strong majority of folks in America and internationally disagree with the idea that salvation is found ONLY in their religion.
....“My faith or religion is the only true path to salvation, liberation or paradise.” Of people in all the countries polled, the only people who poll over 50 percent agreement are Saudis and Indonesians — and in Saudi Arabia, a stunning 25 percent disagree. In the US, only 32 percent agree with this statement.