Final answer:
Isabella and Ferdinand saw the continued secret practice of Judaism and Islam after forced conversions and the presence of non-Christians in the Kingdom of Granada as actions by wicked Christians that must be stopped. This led to the Inquisition and expulsion of Jews and Muslims from Spain.
Step-by-step explanation:
According to Isabella and Ferdinand, wicked Christians took actions that were detrimental to those who were not adherents of their own faith. They perceived actions such as false conversions and secretly continuing to practice faiths other than Christianity, particularly by Jews and Muslims, as threats that needed to be stopped. This led to the implementation of the Inquisition, where religious tolerance was abolished and individuals were forced to convert to Christianity or face expulsion. Moreover, violent campaigns and wars were seen as methods to defend and spread Catholicism, and for territorial gains, as was evident in the expulsion of Muslims from the Kingdom of Granada in 1492. Actions such as warfare, oppression, and instigation of fear among non-Christians were deemed necessary by Ferdinand and Isabella in their role as defenders of the Roman Catholic faith.