Why is it that it's always a Japanese person who gets summoned in an isekai? Simple answer: anime is made in Japan. Same reason aliens speak English in Star Trek.

But there is a reason. Imagine a Pakistani got summoned. He'd reject the goddess as a demon, and refuse to protect the world he's summoned into. He'd say their world is being punished by God for not worshiping him, and start teaching Islam.

It would be a similar story with any sincere Jew or Christian. I'd watch it.