The Orthodox faith in Transylvania at the time of the Union of Alba Julia was under severe threat, Romanians had started to convert to Calvinism and the Greek or Slavic Bishops under Turkish control were unable to defend the faithful.
The people who accepted union with Rome just wanted to save their identity and their Church. It was the Calvinists and not the Papal faction who wanted to Hungarize the Romanian people (many Romanians who converted to Calvinism were eventualy Hungarized, just as the Armenians, but this did not happen with the Romanian Transylvanians who entered union with Rome).
The leaders of the Communist State did now have any loyalty to the Church, it was just a matter of convenience for them to supress the Uniate Church that was seen as a link to the West and to merge it with the largest religious body, not because they liked the Orthodox Church, but because it was a National Church that would be easier to control than a Vatican-supported body.
Some U-word prelates did work closely with the Habsburg authorities but after all they managed to defend the Romanian identity in Transylvania, they actively supported the union movement, etc. However, I don't blame Romanians since it's very hard to understand one's history without nationalist passion.
The truth for me is that Protestantism and its secular values are the biggest threat to Christianity, a powerful, conservative Roman Church in the West and a strong united Orthodox faith in the East are necesary if we want to save the Western culture and values.
Visarion Puiu, the last Romanian-Orthodox Bishop of Chisinau (Besarabia) was one of the most hard-line Orthodox Bishops and an ardent Romanian patriot, he actively opposed the Vatican-Western power before. However, when the Communists took power and they suppressed the U-word Church he had previously opposed, he unmasked their actions. He wrote on the necesity of Church unity (not the kind of "Ecumenism" of our times), Pope Pius XII even offered to make him cardinal, he rejected of course.