I have a few questions:
- What does it mean to be in union with the pope but not part of the Roman or Latin church?
To be in union with the Pope means you agree to everything the Pope (including the Magisterium) teaches. You accept all Catholic Doctrine, making yourself part of the Catholic Church.
The confusion here is that we see the Pope always as the head of the universal Church and at the same time head of the Roman Catholic Church. So people tend to think that the Roman Church is the enitrety of the Catholic Church. Those who are not part of the Roman Church are sui juris Church, or self-governing Churches. The Patriarch of each sui juris Church would run the particular Church the same way the Pope would run the Roman Church, but at the same time the Patriarch much always submit to the teachings of the Pope, so that all Churches are under one faith, one teaching.
- How can those in the Roman/Latin church not deviate one iota in liturgy as prescribed from Rome but other catholic churches in union with Rome have many liturgies?
Its the same way a sui juris Church adhering to the Byzantine Rite cannot have liturgies following the Roman Missal. Liturgies are diversified, owing to separate development through time and tradition in each Church.
- Why does it seem offensive to other catholics to be called Roman catholics?
Some find offense, some find compassion that others are not well educated about the diversity of their faith (if the other person is Catholic)
- Why in the United States are there Roman bishops and other catholic bishops in the same area? It seems to me that if they are in union with Rome they would fall under the same bishop. I can understand the difference in the original countries from ancient times but here we are a modern country.
Part of the responsibility of a local Ordinary is to regulate liturgy. You can’t expect a Roman Bishop regulating the Holy Qurbana or Divine Liturgy.
- Can I as a baptized Roman catholic join another catholic church without offending the Roman church? Or practically saying I prefer another church.
Yes. First, Canon Law is clear that as Catholics we can fulfill the Sunday Obligation by going to any Sunday Liturgy in any Catholic Rite. In the past 5 Sundays of October, I have fulfilled mine going to a Byzantine Divine Liturgy for 3 different Sundays. We also can seek Confession from any priest of our choice, including priests from another Catholic Rite.
Now, if you feel a particular affinity towards an Eastern Church, you can petition your bishop and theirs for a canonical transfer. This means your canonical membership is transfered and now you are subject to the disciplines and laws that govern that Eastern Church. I have a thread about Byzantine Fasting here and that is one such example. As a Roman Catholic I am not expected to follow the fasting calendar of the Ukrainians. But if I become a Ukrainian Catholic, then I follow their fasting calendar but not the Roman one. Not adhering to it is a sin of disobedience. Another is following which days are holidays of obligation. The Byzantine Rite has the 12 great feasts, and each Church would determine which if not all of these feasts are obligatory. The same with the Roman Church which Bishops can dispense or move holidays. But if you are a Ukrainian Catholic you are not expected to go to Liturgy for Immaculate Conception if it is a holiday of obligation in your country set by the Roman Bishops.
Also, as for offending, depends on what you will say in your petition. Some people have sought to become Eastern Catholics out of distate for the OF. That is offensive. But other reasons don’t have to be offensive and would be valid reasons to move to an Eastern Church. It could be that you just find better spirituality in that Church, or their style, discipline and traditions suit you better.
Also note that you can transfer Churches out of marriage. So if you marry a Chaldean, you can become Chaldean if you wish at the time of marriage.