Um, you've got millions of people convinced this is God's will and millions convinced it is the devil's. As Kieren said, no one can prove that God has changed his mind regarding homosexuality. Likewise, no one can prove that God has not touched this man and called him to do this as a means of leading the church in a new direction. Nothing short of a burning bush would change anyone's mind, so there is no real point in debating.
All that can be done is for the members of the church to search their heart and faith for the answer as to whether or not they believe this is God's will. That has happened, and they have decided that God wants this man to be a bishop. For those that disagree, they need to find a new denomination that better fits their concept of God's will.