These Cardinals, these "princes" are attempting to re-set the bar of Constantine for the present day: is the foundation of our faith Baltimore or Christ. It may be, as the author proposes - about Eucharist. It is, I think more about four willing sacrificial "princes" representing - thinking that they lead - a cadre of willingness to trade in Jesus for institutional absolutism. 
They hold and seek to engage the significant residue of selective traditionalists and wavering others to leverage a resolidification of clericalist control as a condition for access to Jesus. In this mentality "mercy" is a concession by institution and its privileged who are free to set, alter, conditions on the presumption of divine right.
They may be convinced in conscience of their rectitude - they have precedent in their predecessors, but their methods betray a mis-reading of the contemporary world where the Spirit is moving and a motive more of self-interest than benevolence or good will.