The patriarchs were not independant to revise the creed agreed on at the council as they saw fit.
With regard to territory, do Irish Catholics go to italian catholic churches and try to convert them into their parishes? Do they setup churches across the street and convince catholics in the other church to stop attending there and start attending across the way? Do they send out a decree that any clergy wishing to leave the irish church may come serve at the italian church no questions asked? Do they dispute the deed claim by the irish church insisting it be given to the italian one?
ALL OF THAT IS HAPPENING IN THE FORMER SOVIET UNION.
That is why the Uniate church is an issue.
No. Because we all consider ourselves one Church. As an Irish-German American, I don't go into an ethnically Italian or Polish or whatever parish with the idea of "converting" anyone. We all have the same faith. Ethnicity in Catholic churches, to the extent that it still really exists, is mostly a matter of immigrants banding together for benefit of common language and customs, not differences in belief. Until 1965, the Mass was the *same* in every way, no matter *what* church one attended. The language was Latin. The parts of the Mass and readings were the same everywhere, for everyone, every day.
Even now, where the vernacular is used, the translations are *supposed* to derive from the same Latin original (though, I'd be the first to admit, the English translation is pretty shaky sometimes). So, again, there is nothing to "convert" to or from.
We don't dispute deeds among ourselves based on ancestry. We're Catholics first, Germans, Italians, Irish, French, etc. a distant second when it comes to matters of religion. Can you say the same? Indeed, the way you pose the question makes it sound like you take as a given, from personal experience, the assumption that such things are expected to take place.
Anticipating your lack of careful reading here, I will acknowledge that there are, doubtless, a few examples of Catholics who do not embody the proper mindset. Fair enough. But these few exceptions are not representative of our Faith, as they clearly don't know it.
This is not the place to do a full-blown discussion on the filioque. Suffice to say that the West saw a need to change the Creed because of the heresy of Adoptionism was returning in Spain. Rome agreed to the formula - unfortunately without consulting the East. In effect, our beliefs have not changed. We still believe that there is ONE principle within the Divine Godhead, not two. I will note that when this was explained to the East at the Council of Florence, it was readily accepted. Personally, I think that the word "through", rather than "and" would better address the issue. I believe, rightfully so, that the East had a valid complaint about the change in formula. But it is more a political issue than a theological one, once the East found that we are still saying what was said at Nicea. Our beliefs didn't change. I consider the Filioque poor judgment and lousy politics on the part of the Pope and the Spanish Bishops, not a heresy...
With regard to territory, do Irish Catholics go to italian catholic churches and try to convert them into their parishes?
I am not familiar with the dispersal of different cultural groups within the former Soviet Union. Here in the US, people once lived in nationalistic "communities" to help facilitate their brothers and sisters from the old world in settling here in the US. Now, there is no mass exodus from Ireland or Italy or Poland. These communities are no longer one nationality, now we have a "melting pot" of people in the formerly "little Italy" or "little Ireland" communities. People here don't consider themselves as Italian first, but Americans (at least the second generation doesn't). Thus, it is hard to make the comparison you are making here.
Do they setup churches across the street and convince catholics in the other church to stop attending there and start attending across the way?
Again, I am not sure whether we can apply the same concept. I don't think there was a DESIRE to raise up a Polish Church in the middle of an Italian neighborhood! We are talking two completely different cultures. And of course, there is only one Catholic Church, so no need to build another one adjacent. And Russia? Are the Ukranian Catholics and Ukranian Orthodox of the same background, culturally speaking? I believe you are comparing apples to oranges, because Catholic and Orthodox are NOT the same religion. I don't see Irish Catholics vs. Italian Catholics as the same comparison as Ukranian Catholics vs Ukranian Orthodox.
We DO have Protestants doing what you describe, though. They DO set up "churches" nearby Catholic ones, they do evangelize, they are sometimes quite active at it. Certainly, it is a hassle, but for one strong in their faith, it is just a hassle. And in reality, it is an opportunity for us to evangelize them! No one I know who is devoted and knows their faith would even consider becoming Protestant. If Orthodox people who are devoted to their faith live nearby a Catholic Church, why are you worried that they will steal the parishoners? I think the only people who leave a particular faith are the ones who were either (a) not very strong in their faith to begin with or (b) are convinced the other church has more claims to the truth presented by Christ.
Regards