I would say he was a lousy Christian. I'd go with Augustine on this. It sounds like you go with the more perfectionist Donatus.
I believe Iscool’s point is that we are told to recognize false teachers by their fruit. If someone buys high church office, then by their very offer to do so, they condemn themselves as false teachers.
No one is perfect, so in judging how their ‘fruit’ relates to being a false teacher, the individual must listen to the Holy Spirit and decide if the fruit is bad enough to merit saying the person is a false teacher.
If buying high church office doesn’t bother you, then you can believe they were true teachers. If it does, then you need to be concerned that they were false teachers - yet allowed and condoned to hold high church office in the Catholic Church.
BTW - NYer wrote: “Christ instructed the Church to preach everything he taught (Matt. 28:19–20) and promised the protection of the Holy Spirit to “guide you into all the truth” (John 16:13).”
Actually, those passages were to his disciples, not a church organization. And while I have no doubt the church will prevail, I see no reason to identify the organization called the Catholic Church as the Church mentioned in the NT. Too much Catholic doctrine comes from the uninspired writings of men, and contradicts the scriptures.