We don't dispute the correct understanding of the Filioque. Our own fathers express the same concept. However, it does not belong in the Creed because it does not express clearly thatas far as His existence is concernedthe Holy Spirit proceeds only from the Father.
The Catholics know that; they do not profess double origin. But I wouldn't put it past the Protestants.
The second reason the Filioque does not belong in the Creed is because it is an unatuhorized change the Fathers knew to probibit precisely because such alterations lead to heresy.
Now, after more than a thousand years of using the Filioque in their Creed, the Catholics are unlikely to just drop it, just as Christains are unlikely to expunge those parts of the bible we know were added at a later date. Part of it is pride, and a large part of it is that no religius group will or can ever admit to being wrong and sruvive.
Oh, my, Kosta, you've told us you do not represent mainline Orthodoxy, and now I'm pretty sure you don't represent Roman Catholicism and its understanding of the Filioque.
Check out New Advent on the Filioque.
Orthodoxy is the odd-man out in this regard.