It is rare and I would agree that this resignation was different from the others. The thing is a lot about the last 50 years has been “unusual”, “different”, etc. I just don’t agree with some others that Benedict was threatened or forced to resign. he did it willingly. It’s just that the former folks don’t want to accept it.
If Benedict had been followed by someone who still continued to believe and preach the Catholic faith, I might be inclined to agree.
The fact is that the formerly rhetorical question, “Is the Pope Catholic?” is no longer rhetorical.