Actually, when quoting this phrase from "the sayings of Jesus," they would not merely quote "peace on earth" as the saying (above) is rendered meaningless without the entire quote. When Xians (and others) allude to the "peace on earth" phrase (mostly around the Xmas holidays), they are not quoting Jesus but a supposed angelic messenger. Her/His/Its message reads, "Glory to God in the highest, and on earth peace, good will toward men."
And they'll fight anyone who disagrees with their "saying."
I will hail fire and sulfur over all your people and kill every single member of your house and your family with great pain and suffering for all eternity, unless you accept my message of peace and love.