...they believe it's man's God-given right and duty to eat animals...
I grew up in a religious family too; I just remind my family that before the fall of man, Adam and Eve lived in... the garden
of Eden. And they ate... the produce
from that garden. It's wasn't until after the fall that God allowed them to eat meat in their fallen state.
Anyway, I'm with you, I'm not here to debate religion. And my family loves me and supports my eating lifestyle, it just always stumps them when I remind them of that story.