A group that believes they're a chosen people of a superior lineage being challenged by an evil, parasitic race committed to the destruction and enslavement of humanity. Sounds a bit like, oh, what they believed in Germany circa the 1930s. Basically It's an ideology of resentment and self-aggrandizement. It gives down and out types the ego boost of belonging to a select, handpicked minority whose suffering is divinely ordained and to be rectified...as well as creating a recognizable enemy to pin all of one's misery and failings onto. Butthurtness and collectivism at its ugliest.