the filoque literally altered the power of god and the trinity. that is a theological change as theology is
the·ol·o·gy
THēˈäləjē/
noun
noun: theology
the study of the nature of God and religious belief.
r
plural noun: theologies
"Augustine assimilated Roman ideals into Christian theology"
Origin
calling it clarification is just a euphemism. if it was simply unclear literally half the christian world wouldn't have split off over it. and papal infallibility is only one aspect of what i linked you to.