The town of Trinity is, according to the Fandom Wiki based on the real location of Oberlin, Ohio Oberlin was founded by two Presbyterian ministers as
> a community of church-centered families who would live simply and according to God's commandments. This community would support a school, to be built for them, that would train preachers and Christian teachers
and was named after Alsation pastor and philanthropist J. F. Oberlin
My reading would be that if the town of Trinity is indeed based on Oberlin, that the relationship with Christianity is 'baked in' to the town from its founding rather than being a later evolution or even necessarily as response to the magical inhabitants, and that the name is meant to underscore that.