Because it is false. Parts of the tradition of the Orthodox are the Epistle of Saint Barnabas and the Didache. These go back to the late first Century or early 2nd. Both are authentic. Indeed, to some early groups, these were canonical. Both condemn homosexuality in the "Way of Death"
Banabas goes even farther. His interpretation of the Jewish dietary laws includes not merely ingratitude, theft, etc, but condemns homosexuality as well.
Any priest marrying homosexuals risked being discovered, defrocked and excommunicated. And this by the people as well as by his bishop and metropolitan.
So much so that the Justinian Code makes homosexuality a capital offense.