I think most of human culture is an appropriation, and often not a very considerate, sometimes even directly malicious appropriation at that. The human tradition of myth and legendry is one long pastiche of a pastiche, with little regard for the sanctity or integrity of the original. Religion is without doubt highly antagonistic cultural appropriation.

Consider: A small group of dissident Jews appropriate myths to create a need for a messiah at a specific time in Judea for the specific purpose of delivering them from oppression. These dissident's beliefs are later appropriated by Gentiles to make the belief system accessible to non-Jews. These Gentile's beliefs, alongside the early Jewish beliefs are later appropriated into the backdrop of another belief system that tells them they're both wrong. Even later, certain Americans start believing the Bible was written in English for white Americans. They launch global terrorism/jihad on anyone who disagrees with 'their' religion.

I don't know that this is right or wrong, I think it is rather an integral way that human beings approach fiction or belief. It causes problems, it foments enmity, but it also enables the relevance of tales to a new audience. Few stories ever remain static, even when free from external appropriation.