I don’t read this poem as a critique of any specific “Pope” as a person, but as a symbol.
A symbol of the developing need, institutions inevitably have, for status and eminence, structure and hierarchy, regulation and control, wealth and influence.
In 380 CE, Church and Empire shook self-interested hands – quid pro quo – mutual commitment and support – though Jesus had said his kingdom wasn’t of this world.
I find in this poem an unusual direction of flow. From the end, to my way of thinking, it goes downhill all the way backward to the beginning!
From the Jesus of History, down to the ‘Christ of Faith’? Institutionalism can so easily obscure, and thus blunt, the sharpness of down-to-earth, practically challenging teachings.