The point has, yet again, been eluded in favor of trying to turn the issue back to non-Catholic Christians and the Gospel. I don't think anyone has suggested, nor imagined, that Roman Catholic Popes were or were expected to be "sinless". That they were expected to BE Christians is not out of the realm of expectations, though. These Popes that have gone down in history (note: not biased nor prejudicial history) as depraved and wicked demonstrated by their ongoing grossly sinful behavior that they were NOT Christians much less qualified to be leaders of the church. We have plenty of Scriptures that outline how a leader within the church is to behave and also the process to be followed when anyone - leadership or not - is to be disciplined when they refuse to repent and continue to bring shame upon the name of Christ.
The issue is why these men were not only elected to their positions by those who knew of their failings but why they were not deposed when their wickedness became public knowledge and scandal? It IS a legitimate question and the slip-sliding evasion of the point is not lost on anyone. I believe it is major proof that the Catholic Church does NOT have their self-defined divine right of carrying on the office of the Apostles with their specific gifts and enablements nor their promises of infallibility by which the "gates of hell" would not prevail. That is the point.
If you read back, my question was what happens to someone who is by his own profession born-again but dies cursing God. Since that, hilariously, was difficult to answer for all till you joined this topic, the diversion was about the bad Popes.
As to them, if you don't like them get your own. On balance, the papacy is about the only one institution around us that is doing splendidly well. I can't think of any world leader today, or in the past couple of centuries worth the footstool of the contemporary to him Pope.