rome was by most every metric an incredibly successful civilization. until the very end, it wasn't christian, and by modern standards was in many ways not overly obsessed with religion. it also employed huge numbers of slaves. a good percentage of them were casually hurt or killed or worked to death, sometimes just for the amusement of others. the argument that slavery is bad because of its negative effects and that you need wide spread empathy for a successful civilization begins to break down when you look at the example of rome.
United States