And still no response from you regarding Mortalium Animos.
Not surprised at this point.
Pius XI flatly forbade any Catholic participation in interchurch or inter-religious meetings and activities motivated by the desire for restoring Christian unity (give-and-take in terms of doctrines.) The Humanum conference, on the other hand, positively encourages Catholics to spread (without weakening or modification) the Catholic understanding of Marriage, as a key to restoring the health of our society: that is, culture and policy.
The "star" Catholic participants are neither theologians nor clerics. Robert George is a philosopher, Mary Ann Glendon a law professor. They are emphatically NOT trying to steer the Church into Protestant theological compromises.
Pius XI strongly emphasized the risks and dangers of indifferentism and confusion about the faith occasioned by interfaith activities based on hashing out a unified doctrinal platform. That’s not what Humanum was about. It was about finding allies in the intellectual and social struggle to restore the unique status of Male-Female complementarity as the basis for natural (Male-Female) marriage. Which is in fact the only kind of real marriage there is as revealed in Natural Law even before it was revealed in Canon Law!!
This was a direct challenge to the "gay" "marriage" ideology.
What Pius XI condemned is by no means the same thing that conferences like Humanum affirm. What, exactly, did Pope Pius condemn as false doctrine?
(1) A "lowest common denominator" approach to achieve one "world religion.”
(2) A denial of the very principle of revealed truth, which presupposes that all approaches are just varying (and fallible) human expressions of a natural religious impulse, and ultimately devalues Divine revelation.
(3) A false ecclesiology: a theological understanding of the Church as "nothing more than a federation of the various Christian communities, even though these may hold different and mutually exclusive doctrines" (MA 6).
(4) The false idea that the unity which Christ prayed for— "Ut unum sint" - —"merely expressed a desire or a prayer which as yet has not been granted. The liberal Protestant ecumenists of the 20th century (and their mistaken Catholic allies) held that the one true Church of Christ has up to their time hardly ever existed and did not exist except as a mere ideal" (MA 7).
To say Humanum conference diverged from the doctrine of Mortalium Animos is to make a category mistake. The Humanum conference was not an ecclesiastical parlay with an aim to getting to a one-world church or a one-church world. It was about strengthen our allies in the truth in order to fight the LGBT agenda.