Which part of morals and faith did they declare infallibly in this situation? Can you show the documents where they are declaring something ex-cathedra?
Hey Mickey:
I appreciate the question because it pushed me to check out a Catholic site defining this doctrine. First, the RCC loves to slam the personal character of Luther (and other reformers), here’s an excerpt from their definition of infallibility:
*It is well further to explain:
Code:
* that infallibility means more than exemption from actual error; it means exemption from the possibility of error;
* that it does not require holiness of life, much less imply impeccability in its organs; sinful and wicked men may be God's agents in defining infallibly;
* and finally that the validity of the Divine guarantee is independent of the fallible arguments upon which a definitive decision may be based, and of the possibly unworthy human motives that in cases of strife may appear to have influenced the result. It is the definitive result itself, and it alone, that is guaranteed to be infallible, not the preliminary stages by which it is reached.
If God bestowed the gift of prophecy on Caiphas who condemned Christ (John 11:49-52; 18:14), surely He may bestow the lesser gift of infallibility even on unworthy human agents.
It is, therefore, a mere waste of time for opponents of infallibility to try to create a prejudice against the Catholic claim by pointing out the moral or intellectual shortcomings of popes or councils that have pronounced definitive doctrinal decisions, or to try to show historically that such decisions in certain cases were the seemingly natural and inevitable outcome of existing conditions, moral, intellectual, and political.*
newadvent.org/cathen/07790a.htm
With regard to your assertions “Sacred Magisterium” is also a component of infallibility. This includes:
“The task of interpreting the Word of God authentically has been entrusted solely to the Magisterium of the Church, that is, to the Pope and to the bishops in communion with him” (Catechism of the Catholic Church, 2nd ed. 1997, pt. 1, sect. 1, ch. 2, art. 2, III #100]).
"Ordinary and Universal Magisterium (not to be confused with “ordinary Magisterium”) also falls under “Sacred Magisterium” (thankfully I have a law degree – one has to be a lawyer to sort through all of this

).
So – interpreting scripture does fall under infallibility. This power is exercised not only in declarations but also through the churches actions (by the churches own definition). Hence there is ample support for the idea that the Galileo question does logically debunk infallibility.
The problem here is the church often defines what is “ordinary and universal” as opposed to merely “ordinary” (which is not infallible) ex post facto. Moreover, it does so in a subjective way – which allows it to deny error in all cases (after the fact).
We can see this in the history of the church. For example, when an assault is launched on infallibility as defined by something like Vatican I – the church will later “further clarify” the doctrine in a way that refutes those charges in later councils (such as Vatican II).
A declaration of an infallible interpretation formed the basis for the charges against Galileo – charging he refuted those official declarations by his scientific theory (nothing else could form the bases for such charges by an official church body like the inquisition – or else Galileo could have used that as a defense to rebut the charges).
Then, later in history the church calls itself infallible. Then an outpouring of criticism of the doctrine emerges (such as with regard to the Galileo affair), so they redefine it (under the guise that they’re merely clarifying it).
Can you see my point? This is not intellectually honest & it is a valid criticism.