Quoting Moss, again, With a Comment

Moss:

It was one thing to remove the bans on the old rites, as ROCOR had done in its Council in 1974: it was quite another to recognise the schismatics as Orthodox. And in such terms! For later in the epistle ROCOR compares the persecutions of the Old Ritualists to the persecutions of St. John Chrysostom, and begs forgiveness of the Old Ritualists as the Emperor Theodosius the Younger had begged it of the holy hierarch! But, as Bishop Gregory Grabbe pointed out after the 1974 Council, the sins of the Russian State in persecuting the Old Ritualists in the 17th century should not all be laid on the Church of the time, which primarily condemned the Old Ritualists not for their adherence to the old rites (which even Patriarch Nicon recognised to be salvific), but for their disobedience to the Church. To lay all the blame for the schism, not on the Old Ritualists but on the Orthodox, even after the Old Ritualists had proudly refused to take advantage of the many major concessions made by the Orthodox (for example, the edinoverie) while stubbornly continuing to call the Orthodox themselves schismatics, was to invert the truth and logically led to the conclusion that the Orthodox Church was not the True Church!

Me

And how is edinoverie different from Uniatism?

How is the Russian condemnation of Uniatism different from the Bespopovtsi condemnation of edinoverie?

Well, perhaps in this : Avvakum retained the position of Gregory Palamas, which Pope Pius IX of blessed memory in 1854 made binding dogma in the Catholic Church.

What was required at edinoverie was giving that up.

However, the position of Photius in Mystagogy cannot be considered as equal with Gregory Palamas, since Photius was ignoring the position, not only of St Augustine of Hippo (whom he had called a saint in Vivliothiki!) but of several saints, including Saint Athanasius, who was not even a Westerner.

Trento - Philaret (Catechisms) : Filioque far older than III Council of Toledo
http://trentophilaret.blogspot.com/p/filioque-far-older-than-iii-council-of.html

Trento - Philaret (Catechisms) : Mone hagne, mone eulogemene / Moni agni, moni evloyimeni
http://trentophilaret.blogspot.com/p/mone-hagne-mone-eulogemene-moni-agni.html