Please, don’t consider this to be a parallel. I am going to drop a little information about how “to be forced” is felt when speaking about Byzantine unions in Slavic world + Hungary, especially where west and east met and unions were established.
For example in remote parts of Slovakia and Carpathian Rus (now the most Western part of Ukraine), Galicia… altogether where Rusins live there is sometimes tendention to say that Sts. Cyril and Methodius were OK with Rome, even ordained and established archbishop of Great Moravia and Panonia by Rome. People there followed thier approach and when official Byzantine influence was removed, they were trying to be Byzantine (more exactly “as fathers did”) as well as “Roman friendly”. Later they were “catched” by Orthodox bishops, but they were trying their best even under these circumstances and Union was just public declaration when also hierarchy addopted official Catholic standing. (Some were catched by Latin bishops.) However, this was never officialy stated.
Of course Orthodox cannot agree with this, pointing out that Cyril and Methodius were Orthodox and living in times when Rome was in communion, and their followers were Orthodox until not brought to Union.
It seems to be that unions of Ruthenians, Slovaks… were not forced and not rarely all the clergy said their yes and there were no problems and Greek Catholics say this was their happy decision, no forcement. (Later latinisation is another topic.) In Slovakia, where Orthodox Church earned bad image during communism, Orthodox maximally say that people were lied. In Ukraine they are more able to “fit hisotry”. I think that these unions were voluntary for clergy and people just followed.
Unions taking place more east were not so full 100 % agreed, maybe one or two bishops did not give their signature but they were not punished (well, maybe there was parallel Catholic bishop but these ones were not sent to prison). Catholic monarchs supported Catholics and Orthodox remained unsupported but open persecution was not usual. Orthodox had not so easy living but were tollerated. Exceptions existed. It could have been problem if converting from Catholicism was illegal, but individuals switching were very rare, bishops switching with whole communities were the norm.
When some territories were taken back by Russians, situation was probably harder for Catholics than for Orthodox before. Somewhere were synods but often a) less enthusiastic, or b) just partly supported and not (nearly) unanimous as before. Exceptions existed. Trend look likes move O–>C was easier and more voluntary than C–>O. There were nearly no martyrs for Orthodoxy at first switch but if there was second switch back to Orthodoxy, there were usually martyrs and “rebel” bishops and priests.
Now when we focus on situation of Orthodox e. g. in Austro-Hungarian monarchy ruled by Catholic emperors or kings: Orthodox were officialy tolerated (in their own remote areas + maybe one church in capital) but very unsupported. One statistic says that in what is now Eparchy of Košice (Slovakia) there were only 5 Orthodox in 1900. But to the end of 19th century, sometimes someone met Orthodoxy abroad and returned home as propagator of coming home from unfortunate union. It was not massive but a few parishes switched. Some of this “switch supporters” were executed as Russian spies. If Orthodox in Slovakia want to show they were bad treated, they show this.
After WW I quite OK. In former Czecho-Slovakia state wanted its own state Rome-free church. This was less successful than expected but some exCatholics became Orthodox and not state-Protestants, however there were only few Orthodox.
When communists came to power, Greek Catholic Church was usually declared illegal and some quasisynods (e. g. no bishops, 7 % of priests, commisions needed just 5 minutes to elaborate documents which need usually years to be prepared, portraits of communist leaders where synod took place etc.) even declared comming home from evil Rome. Some GCs accepted, many pretended to be Latins not to be Orthodox, some went in catacomb status…, bishops and most of priests enprisoned, some tortured and martyred by prison. When GCC was later allowed, churhc just switched illegal to legal existence.
After turn to capitalism was made (if you preffer, you can call it democracy), situation was different: in Slovakia GCC was given back its churches and buildings and number of Orthodox droped to 50 % and Orthodox started to pretend they are greatest martyrs in the world because of this. In Ukraine GCC was made legal but no churches given back.
I think that in countries where Orthodox renome was damaged by communism nearly noone believes in forced unions + they do not seem to be forced. In countries where Orthodox are better established, they are more in force to proclaim more pro-Orthodox interpretations. This is stronger moving east as well as ratio of spontanuous and unanious unions is decreasing when moving east.
This is not situations of e. g. Bulgaria where there are few GC since 19th centrury, or of Croatia were there is/was another context.
