The term "fungible" refers to the  interchangeability of objects in the psychic lives of groups and individuals. When people attach to an omnipotently conceived object and perform violent acts, a common mechanism is operative--regardless of the nature of the object. The phrase "death to the non-believers" conveys the central meaning. Members of one group seek to kill members of an other group that does not bow down to the sacred object worshipped by one's own group.