Even if we were to agree with you that Aquinas taught that, it is still the private interpretation of a private theologian and carries no official weight.
I was using that conclusion to shed light upon the different theological frameworks and methodologies at work here. For an example of an unambiguously dogmatic disagreement, I would cite his work Against the Greeks which advocates the Filioque and Papal Supremacy.
We cannot forget that every doctrine has implicit Trinitarian and Christological implications. Papal infallibility, for example, is the restriction of a particular divine charism/energy (not transmitted through Holy Orders) to one episcopal office, which is hard to map onto an Eastern framework.
