Benedict was getting a lot of flak for that in his last year, especially from Poles and Romani and other Catholic groups that were specifically targeted in the Holocaust. Then there was the fact that some of the worst child abuse cases came to light on his watch, and so did the fact that he helped sweep those cases under the rug.

I don't have any proof, but I feel like he felt that if he stayed in power he'd risk a major schism or at least compromise the Church's activities in the global south.