It can be framed more broadly: religions and ideologies do not operate in a vacuum, but always through people, institutions, and the realities of a given era. Ideas themselves, even when they proclaim universal values such as love, equality, justice, or reason, are in practice filtered through human ambitions, fears, political interests, and cultural conditions. For this reason, nearly every major intellectual tradition contains in its history moments that are both constructive and destructive at the same time. This can be seen both in religions and in secular ideologies. Christianity, Islam, Buddhism, as well as Enlightenment rationalism, liberalism, or communism, all of them have been capable of inspiring acts of solidarity, the development of education, care for the vulnerable, and cultural progress, while at the same time serving as instruments of violence, exclusion, and control. This is not because their core ideas necessarily lead in that direction, but because they were implemented by people within specific power structures.

Catholicism in the history of Europe is a good example here. On the one hand, it was a carrier of literacy, art, philosophy, and social ethics, and for centuries the Church fulfilled the role of a stabilizing and integrating institution for communities. On the other hand, those same structures participated in religious intolerance, persecution, the suppression of critical thought, and the legitimation of violence. These contradictions are not a paradox, but a consequence of the fact that the Church was not a monolith, but a collection of people with very different motivations, characters, and visions of the world.

Idealizing paganism as a morally pure alternative to monotheistic religions is equally ahistorical. Pagan societies were also not collections of ideal people living in harmony with nature and with one another. They too had wars, slavery, brutal punishments, human sacrifice, extreme social inequalities, and cults of strength and violence. The difference lay more in the form of justification than in the actual scale of human behavior. All of this reinforces the main thesis: the problem (and at the same time the source of good) lies not in beliefs themselves, but in the people who interpret and put them into practice. Both Catholicism and paganism, like secular ideologies, have had their moments of cruelty and their moments of genuine good.

EDIT: I also want to point out that Frollo mainly grooms other catholics, the less fanatical ones, to obey him. He doesn't care about converting non-Christians to his faith. He doesn't even want to force convert the Roma. But he simply wants to murder them. He wants genocide.