He did not make such a black and white condemnation. Pope Pius answering a very specific question. “If they all believe in Christ, what difference does it make whether one is Anglican or Catholic, Lutheran or Catholic, etc.?” It was a question about relativism.
The condemnation was made nonetheless, correct? Here is how it reads:
1717 17. We must have at least good hope concerning the eternal salvation of all those who in no wise are in the true Church of Christ 13. [see n. 1646] 28 [see n. 1677]. (Denzinger EN 1717)
1646 Not without sorrow we have learned that another error, no less destructive, has taken possession of some parts of the Catholic world, and has taken up its abode in the souls of many Catholics who think that one should have good hope of the eternal salvation of all those who have never lived in the true Church of Christ [see n. 1717]. Therefore, they are wont to ask very often what will be the lot and condition after death of those who have not submitted in any way to the Catholic faith, and, by bringing forward most vain reasons, they make a response favorable to their false opinion. Far be it from Us, Venerable Brethren, to presume on the limits of the divine mercy which is infinite; far from Us, to wish to scrutinize the hidden counsel and “judgments of God” which are 'a great deep" ( Ps. PS 35,7) and cannot be penetrated by human thought. But, as is Our Apostolic duty, we wish your episcopal solicitude and vigilance to be aroused, so that you will strive as much as you can to drive from the mind of men that impious and equally fatal opinion, namely, that the way of eternal salvation can be found in any religion whatsoever. May you demonstrate with that skill and learning in which you excel, to the people entrusted to your care that the dogmas of the Catholic faith are in no wise opposed to divine mercy and justice.(Denzinger EN 1646) {
emphasis mine}
1647
For, it must be held by faith that outside the Apostolic Roman Church, no one can be saved; that this is the only ark of salvation; that he who shall not have entered therein will perish in the flood; but, on the other hand, it is necessary to hold for certain that they who labor in ignorance of the true religion, if this ignorance is invincible, are not stained by any guilt in this matter in the eyes of God. Now, in truth, who would arrogate so much to himself as to mark the limits of such an ignorance, because of the nature and variety of peoples, regions, innate dispositions, and of so many other things? For, in truth, when released from these corporeal chains “we shall see God as He is” (1JN 3,2), we shall understand perfectly by how close and beautiful a bond divine mercy and justice are united; but, as long as we are on earth, weighed down by this mortal mass which blunts the soul, let us hold most firmly that, in accordance with Catholic teaching, there is “one God, one faith, one baptism” ( Eph. EP 4,5); it is unlawful to proceed further in inquiry. (Denzinger EN 1647){
emphasis mine}
1648 But, just as the way of charity demands, let us pour forth continual prayers that all nations everywhere may be converted to Christ; and let us be devoted to the common salvation of men in proportion to our strength, “for the hand of the Lord is not shortened” (IS 9,1) and the gifts of heavenly grace will not be wanting those who sincerely wish and ask to be refreshed by this light. *Truths of this sort should be deeply fixed in the minds of the faithful, lest they be corrupted by false doctrines, whose object is to foster an indifference toward religion, which we see spreading widely and growing strong for the destruction of souls. *(Denzinger EN 1648){
emphasis mine}
1677 And here, beloved Sons and Venerable Brothers, We should mention again and censure a very grave error in which some Catholics are unhappily engaged, who believe that men living in error, and separated from the true faith and from Catholic unity, can attain eternal life [see n. 1717]. Indeed, this is certainly quite contrary to Catholic teaching. It is known to Us and to you that they who labor in invincible ignorance of our most holy religion and who, zealously keeping the natural law and its precepts engraved in the hearts of all by God, and being ready to obey God, live an honest and upright life, can, by the operating power of divine light and grace, attain eternal life, since God who clearly beholds, searches, and knows the minds, souls, thoughts, and habits of all men, because of His great goodness and mercy, will by no means suffer anyone to be punished with eternal torment who has not the guilt of deliberate sin. But, the Catholic dogma that no one can be saved outside the Catholic Church is well-known; and also that those who are obstinate toward the authority and definitions of the same Church, and who persistently separate themselves from the unity of the Church, and from the Roman Pontiff, the successor of PETER, to whom “the guardianship of the vine has been entrusted by the Savior,” * cannot obtain eternal salvation.(Denzinger EN 1677)
Brother JR, I am not sure what source you have used that has these alleged ambiguities in what Pope Pius IX addressed, but no. 17 seems rather “black and white” to me. Could you lead me to where you might have found these said ambiguities?
Every couple of decades, maybe more frequently, relativism shows its ugly head. It is one thing to say that one should not believe that the non Catholic Churches and ecclesial communities do not have the fullness of faith and quite another to say that non Catholics cannot be saved.
To be clear, when you speak of this relativism, are you speaking in regards to the Church, or in regards to society at large?
God be with you.