How do you blackmail a Pope?
I believe Benedict was blackmailed for his own homosexuality and his affairs with men (and possibly boys, but that is speculation). The Italian press printed rivers of ink on the subject of Benedict being ousted in what was basically a coup,but they alleged he was blackmailed because he didn’t handle other priests homosexuality in the right matter. I never believed that for an instant. Mismanagement of anything would not be damning enough to make him resign. He was blackmailed for something far, far worse. The whole lie about Benedict having to step down because of poker health was the cover story.
Threaten his family
Perhaps popes aren’t infallible, after all.