Don't forget that reversed stupidity is not intelligence; a belief doesn't become wrong simply because it's widely held by Catholics.

Similarly, there's no need to be scared of responding positively to art or other ideas because they originated from a religious perspective; if atheism required us to do that, it would be almost as bleak a worldview as it's accused of being. Adeste Fideles doesn't stop being a beautiful song when you realize its symbols don't have referents. I think of the Christian mythology as one of my primary fantasy influences—like The Lord of the Rings, Discworld, The Chronicles of Thomas Covenant or Doctor Who—so, if I find myself reacting emotionally to a Christian meme, I don't have to worry that I'm having a conversion experience (or that God exists and is sneakily trying to win me over!): it's perfectly normal, and lawful, for works of fiction to have emotional impact.