A lot of Popes became Pope for power. I don’t know how the video game depicts it, but Alexander VI was certainly one of those who used the Papacy to consolidate power, enrich his family, install some of his children in positions so that they could continue the dynasty, and did many things that a lot of believers would probably consider very un-Christian. I don’t know if he hated Christianity, though. I would guess that he didn’t since it gave him not only ecclesiastical, but temporal power.