Unfortunately the reasoning of St. Thomas C. is pointless to today's standards. Acting and behaving like a pope is subject to today's relativism and boils down to: What is a pope supposed to behave as? And Peter is subject to the duties of the Office. I presume he means formal duties as described in certain documents. Or does he mean he is subject to the then ruling morality viewed as logical in that time, as a result of an interpretation from that time by St Thomas, of existing documents like the bible and the catechism. And you may notice the Pope changing interpretations in his binding motu proprios in such a way that the morality as seen from the Vatican changes in such a way that Francis objectively seen complies with the fallacy of St. Thomas C. So.. even according to today's standards, Francis behaves like a pope and is subject to the duties of the office. The rest is a question of taste. If it tastes bad, then its your problem. Legally it is watertight. They know what they do. By any standard they are relativists.

St. Thomas Cajetan, O.P. (1469-1534)
Theologian and Cardinal

He points out that the famous axiom "Ubi Petrus, ibi Ecclesia" (Where the Pope is, there is also the Church) holds true only when he acts and behaves as the Pope, because Peter "is subject to the duties of the Office" otherwise,"neither is the Church in him, nor is he in the Church."