The Index became an albatross and was a point of contention by the enemies of the Church. Basically the Pope was pressured. Why any Pope would "remove" anything from the Index is anyone's guess, but more importantly, it must be addressed that the Pope could only remove things once they had been corrected. That never happened, yet he unbound the consciences of men in the matter. So, what do we do with that? I guess there's a little more hope for those who cannot understand that an indoctrination was foisted on them and God permitted this for their sake. Kind of like Moses permitting divorce for a time. However, Scripture tells us that Moses permitted it because it was out of the hardness of their hearts. IMHO we ought to respect tradition and refuse the option that resulted from a modernization of the Church and her prelates. There is no need to find ourselves pining over a dead subject like heliocentrism. It is a retarded pagan doctrine that continues to usher in the nєω ωσrℓ∂ σr∂єr. Ain't nobody got time for that.
So the Index has "moral force" when a book you disapprove of is put on it, but when the book is removed you want to explain it away?
The scientific understanding of heliocentrism had changed by the time the books were removed from the Index. Most likely that is why the Pope had it done, even without the corrections being added to the books.
At any rate, there are no grounds for claiming that Catholics may not believe heliocentrism.