"How can they be fully Catholic when they use the Creed without the filioque?"
Well, the Catholic Church has never imposed the Eastern Catholic Church to include the filioque in the creed. This is because with or without it the faith would be the same.
The truth is that the Orthodox party wanted to have an exuse to separate from Rome (under the emperor pressure that wanted to controll the Church) and accused Rome of a meaningless theological accusation.
These are few citations from the Latin and Greek fathers of the Church that say the same thing and support the filioque.
Hilary of Poitiers
"Concerning the Holy Spirit . . . it is not necessary to speak of him who must be acknowledged, who is from the Father and the Son, his sources" (The Trinity 2:29 [A.D. 357]).
Epiphanius of Salamis
"The Father always existed and the Son always existed, and the Spirit breathes from the Father and the Son" (The Man Well-Anchored 75 [A.D. 374]).
Ambrose of Milan
"The Holy Spirit, when he proceeds from the Father and the Son, does not separate himself from the Father and does not separate himself from the Son" ((The Holy Spirit , 1:2:120 [A.D. 381]).
The Athanasian Creed
"[W]e venerate one God in the Trinity, and the Trinity in oneness. . . . The Father was not made nor created nor begotten by anyone. The Son is from the Father alone, not made nor created, but begotten. The Holy Spirit is from the Father and the Son, not made nor created nor begotten, but proceeding" (Athanasian Creed [A.D. 400]).
Augustine
"[The one] from whom principally the Holy Spirit proceeds is called God the Father. I have added the term ‘principally’ because the Holy Spirit is found to proceed also from the Son" (ibid., 15:17:29).
"Why, then, should we not believe that the Holy Spirit proceeds also from the Son, when he is the Spirit also of the Son? For if the Holy Spirit did not proceed from him, when he showed himself to his disciples after his resurrection he would not have breathed upon them, saying, ‘Receive the Holy Spirit’ [John 20:22]. For what else did he signify by that breathing upon them except that the Holy Spirit proceeds also from him" (Homilies on John 99:8 [A.D. 416]).
Cyril of Alexandria
"Since the Holy Spirit when he is in us effects our being conformed to God, and he actually proceeds from the Father and Son, it is abundantly clear that he is of the divine essence, in it in essence and proceeding from it" (Treasury of the Holy Trinity, thesis 34 [A.D. 424]).
Council of Toledo
"We believe in one true God, Father and Son and Holy Spirit, maker of the visible and the invisible.
. . . The Spirit is also the Paraclete, who is himself neither the Father nor the Son, but proceeding from the Father and the Son. Therefore the Father is unbegotten, the Son is begotten, the Paraclete is not begotten but proceeding from the Father and the Son" (Council of Toledo [A.D. 447]).
You always accuse the Catholic Church of having changed the faith, but it is me who continuously cite the fathers of the Church. When, I asked you a citation that would support your claim (divorce and remarriage, etc) you have done us nothing.
Are you so sure that it is the Catholic Church to have changed the faith? Why do the Fathers agree with the Catholic Church?
"No one was there to help and "give us water."
Are you sure for that? The Popes have done what they could to help the Orthodox from the Turks and the communist. When Constantinople collapsed it was defended by Catholic armies that were present even if small in number because of the arrogance of the Orthodox patriarch, The Ottoman empire was defeated and then collapsed because defeated by Western and Catholic armies, the communist collapsed because of the Western and Catholic pressure. Finally, the Catholic Church has always prayed from the Orthodox.
But you never say “thank you.”
That is not true. It is only recently (check Internet sites) that Eastern Catholics and Melkites have dropped the filioque.
The truth is that the Orthodox party wanted to have an excuse to separate from Rome
That's pathetic. You have no proof of such a claim, because there isn't one. I really don't think you know the detailed history of the Church in the first millennium.
and accused Rome of a meaningless theological accusation
You also do not understand the issue of filioque. But as I said, that's another thread.
These are few citations from the Latin and Greek fathers of the Church that say the same thing and support the filioque
Not as regards His {the Holy Spirit's] existence.
You also do not understand the difference between the His Origin and his precedence as manifested in Divine Economy of our salvation.
The Fathers were speaking of the latter. You are mixing apples and oranges because you don't understand what filioque means. The Fathers understood it. That's obvious from their writing. They did not talk about His eternal coming into existence, which is from the Father alone.
The Popes have done what they could to help the Orthodox from the Turks and the communist.
By establishing the Latin Empire in Constantinople, or by encouraging and supporting Maria Theresa of Austria to create what you now insist on calling "Eastern Catholic" churches, or by beatifying cardinal Stepinac of Croatia?
Thanks would be appropriate if what the Popes offered was truly help. Thanks were expressed for returning the relics of two saints by JPII.
Unlike you and some other members of your Church, who may be actually on the periphery of it, most of the Roman Catholics and Eastern Orthodox are content with putting the past behind us and seeking fraternal recognition of one and the same Church in each other, but without confusion or absorption.
You may find it quite joyful to do the same. I hope you do. I will now end my dialog with you on this positive note, in hopes that we can meet next time as brothers and not as adversaries.