Not sure that's a Protestantisation. Not like Catholics haven't been ambivalent about many Popes in the past: Dante in the Comedy put Pope Boniface VIII in hell.
It is one thing to mock an ex Pope - the Catholic Church itself has picked who was and was not Pope post facto, for a variety of reasons. But if the current “Vicar of Christ” is mediocre at best, why on earth or in heaven would you recognize his authority?
Except that in the same canto Dante puts Clement V beside Boniface VIII, and Clement V was the reigning Pope at the time the Inferno was written.
Actually Dante had much sympathy towards the Emperor and very little towards the Popes for a Guelph... indeed in one of the most famous verses of Italian literature, Ugo Foscolo called him a
ghibellin fuggiasco (fleeing Ghibelline).