I do not agree with your views on the attitude of Pius XI and earlier Popes vis avis ecumenism.  What they spelled out as their policies towards non-Catholics did not represent Divine Law, but rather the discipline they thought necessary to maintain the requirements of Divine Law.  I don't know whether you were aware of this, but in the 4th Century the Popes mandated reception of Communion under both kinds in the city of Rome because the Manicheans (who considered wine to be evil) refused to receive the cup.  At that time, the Pope enforced the discipline so that it was a serious sin to refuse the Precious Blood because such refusal was a sign of allegiance to the Manichean heresy.

Times have changed.  We are in a different world now.  Catholics are no longer isolated from other religions by geography and social strata.  We need to learn to live together with people who will most likely not convert to the True Faith.  We must still evangelize, but we must also learn to live in a pluralistic world until God decides to convert the world to Christ through his grace.  In the meantime, we must lay the ground work for corporate reunion between ourselves and our Separated Brethren in other Christian sects and Churches.

To accomplish these ends, we need a new way of dealing with non-Catholics other than the triumphalism of the past.  This is not the first time that the Popes have set out on a program that seemed to contradict previous policy.  It happened when the Church was recognized by the Roman Empire as state religion after being persecuted for centuries.  It happened when Popes reversed their initial decision on the matter and authorized the addition of the "filioque" to the Niceo-Constantinopolitan Creed.  It happened when Pope Pius V broke with Latin Rite traditions, suppressed local liturgical rites, and implemented the Roman Missal on the entire Latin Rite with only a few exceptions.

This why we have Popes.  They are supposed to lead us where God wants the Church to go in the here-and-now.  It is not proper to compare the disciplinary standards of a former time to our time in contradiction to the Pope's directives.

I see no contradiction in what the Magisterium is currently doing with regard to ecumenism and the defined dogmatic teachings of the past.  I think it is time to quit arguing about Vatican II and accept its authority along with that of the other recent documents of the Magisterium.

Roma locuta est, causa finita est.