Let's read St. Robert Bellarmine on the subject:
‘Third. I say that if there were a true demonstration that the sun was in the centre of the universe and the Earth in the third sphere, and that the sun did not travel around the Earth but the Earth circled the sun, then it would be necessary to proceed with great caution in explaining the passages of Scripture which seemed contrary, and we would rather have to say that we did not understand them than to say that something was false which has been demonstrated. But as for myself, I do not believe that there is any such demonstration; none has been shown to me. It is not the same thing to show that the appearances are saved by assuming that the sun is at the centre and the Earth is in the heavens, as it is to demonstrate that the sun really is in the centre and the Earth in the heavens. I believe that the first demonstration might exist, but I have grave doubts about the second, and in a case of doubt, one may not depart from the Scriptures as explained by the holy Fathers
So, basically, what they were condemning is the assertion that Sacred Scripture was false implicit in Galileo's theories ... and the fact that his theories did not have any real proof. So, reading the above, there was clearly no absolute ruling regarding the truth or falsehood of heliocentrism, and what was being condemned was the implicit allegation that Sacred Scripture was wrong. And indeed the competence of the Magisterium has for its primary object matters of faith and morals, rather than natural science. So the primary object of this condemnation was a matter of faith and morals, that Sacred Scripture might be in error, rather than the teaching of any particular scientific matter.
You could say that if Bellarmine's letter came AFTER the 1616 decree. However it was written in 1615 one year before the Pope gave his definition of formal heresy. Even if Bellarmine meant what the Galileans make him say, it became REDUNDANT one year later in 1616.
Interestingly Ladislaus the above passage is nearly always used by the Galileans to dismiss the decree as soon as they believed proof was found. They all used it, John Paul II and all. This letter was origionally written to dismiss the idea that Galileo had proof, and is in the present tense. The Heliocentrists actually write it up in this way: 'If there were EVER proof for a moving earth...' They always take it out of context to make it apply to any time in the future and not the present time Bellarmine wrote it. They never repeat Bellarmine's belief that there is no proof and that no proof will ever be found.
Finally, I have grave problems myself with this sort of theology if we can call it that conjured up by the helios, even JPII. What if we were to apply that thinking (if there were ever proof then) to any other dogmas of the Catholic faith? You could EQUALLY say that 'IF EVER THERE WAS PROOF THAT ADAM AND EVE NEVER EXISTED WE WOULD HAVE TO RECONSIDER THE DOGMA OF ORIGINAL SIN' or 'IF EVER PROOF THAT JESUS NEVER ACTUALLY DIED ON THE CROSS, WE WOULD HAVE TO RECONSIDER THAT DOGMA.'
See what I mean?