This isn’t about humility, it’s about authority, truth, and right order. The giving and receiving of blessings is relational: blessings are given by a superior, to demonstrate approval, good will, or a desire to convey the spiritual gifts with which one’s entrusted. Thus priests bless lay people and parents bless (their own) children. A revered teacher might bless an exceptional pupil. For the pope to accept a blessing from the ABC is an inversion of right order, degrading a spiritual action to the level of just a more ceremonial way of shaking hands. It doesn’t demonstrate humility on Francis’s part; it demonstrates ignorance, loss of continuity with his past, and disregard for the state of life to which God’s called him.
How do you construe the “benedicimus te” in the Gloria?