content: There is an age-old ritual of community building. A group picks another group and declares them the out group, using statements like OP. Our tribe is better than their tribe. It helps to create the rules that turn into a culture and mores. It's the reason our ancestors were willing to murder other protohumans. It has real purpose, but it also causes great evil. All that's necessary to create conflict between two different groups of humans is to define the groups.