To answer the original question, the Catholic traditon is to condemn and denounce actions and non-values, not people. When you denounce or condemn anyone by name, you are violating a moral principle.
As to whether or not the pope can or should be put on triabl by a secular government, there is an ancient regulation here that applies to all Catholics. No pope is ever subject to any temporal authority. Therefore, any Catholic who sustaines this point of view is reducing the papacy and the person to holds the office to a subject of another temporal leader. Only the subject of a temporal authority can be judged by a temporal authority. Popes are not subjects of temporal authorities. They are Vicars of Jesus Christ, which places them at the head of the Church on earth and above all temporal authorities.
The only way that a Catholic can morally approve of putting a pope on trial would be for the person who holds the office to abdicate. Then he would no longer be pope. He returns to the ranks of the College of Bishops. As long as he is pope, his superior to the College of Bishops.
Another way of understanding it is this, the pope is the Vicar of Jesus Christ. Jesus is not subject to any temporal authority unless he chooses to be. As he said to Pilate, “You have authority over me, because it has been given to you from above.” The same applies to Peter. Only authority that has been assigned from above can judge Peter, since Peter is the visible head of the Mystical Body. You can’t place the head on trial without placing the body. To place a pope on trial is to place the Mystical Body on trial, since he is the temporal head of that body, with Christ as it’s true head, of course. But he is the temporal head by Divine design, not human design.
Can a pope be made to retire or resign? No, never. If he is canonically elected, the bishops cannot ask for his resignation, even if he were the worse criminal in the world. He remains the Vicar of Jesus Christ and is answerable to no one in the Church. He is not even accountable to Church law, because he is the Law-Giver. He is only accountable for his soul, as is every other sinner. Like every other sinner, he is not accountable to the world for his sins, only to God and the Church, through his confessor, not outside of confession.
Let’s just assume that all of the allegations against Pope Benedict were true, he remains the Vicar of Jesus Christ. His authority is indisputed. His teachings on faith and morals continue to be infallible, because he cannot teach error. He continues to be the Law Giver and he continues to have the power and the Divine Right to demand obedience of Catholics.
A pope’s sins do nothing to diminish his office and his power. Ironically, he can even excommunicate another person for the same sin that he may have committed and the excommuncation is valid and binding, until lifted by another pope.
To close, you cannot denounce or condemn people, only behaviors and non-values. We cannot submit the Vicar of Christ to temporal authorities, because as Vicar of Christ he is no one’s subject except Christ’s. He cannot be deposed by anyone, because there is no authority that can judge him. The only way out, would be for a council to declare that he is not a valid pope. Then he returns to the ranks of the bishops and has to submit to all the authority that any bishop must submit to.
I hope this helps.
Fraternally,
Br. JR, OSF