Warhammer 40000 fireblade

The Emperor's Children, also sometimes known after their fall as the Lords of Profligacy, are a Traitor Legion of Chaos Space Marines who devote themselves solely. Some wording in the new Genestealer Cult preview (https://www.warhammer-community.com/2017/05/27/warhammer-40000-faction-focus-genestealer-cults/) has me wondering.