What if Amazing Grace was written by someone of a different religion or movement? You might have "Amazing Enlightenment" or "Amazing Jihad" or "Amazing Non-being"! How about "Amazing Humans"? Verses are already coming to mind, some unprintable (to me)! Would we still sing it? The melody stays the same. There is no such thing as a right tune or a wrong tune. The words determine whether the music is appropriate or not. I was really shocked when I learned that the stereotypical circus tune was entitled "Enter the Gladiator"! To me it just does not fit. But, Hey! That's just my opinion. Attack the message, not the mortal frame that bears it.