Stalin killed thousands of Ukrainian Catholic priests, and tried to annex the rest to the Moscow Patriarchate by force.
If you read the works of good Ukrainian Catholics like Josyp Terelya (23 years in the Gulag), they’ll tell you that Moscow Patriarchate priests had to collaborate with the KGB.
Nowadays, false ecumenism requires heretical statements like “Balamand,” declarations that Catholic prelates in Russia are not “proselytizing,” and, in deference to Moscow, the refusal to recognize a Ukrainian Catholic patriarchate even though the Ukrainian Catholic Church is the largest Catholic Eastern church.
We must pray for the conversion of Russia and Ukraine to the true faith, and we’re called “pre-Vatican II” or fundamentalists, so be it.