The Popes are just a vestige of the last Caesar most of which were corrupt, at one time there were 5 Popes in europe at the same time which disproves the entire 'appointed by God' shtick as does the numerous wars the Pope's have inflicted upon europe. One can draw a line from those wars to the 'Freedom of Religion' amendment in the BOR . Having said that I'll note that it is not the religion's fault if it is used by evil sociopaths to elevate themselves above others, free will is a double edged sword.
There can be no perfect belief system because humans are not perfect