From the article:
"Being a Shiite, as most Iraqi Arabs are, meets the standard (i.e. the failure to view the Koran exactly in accordance with the Sunni beliefs) as well, because the Islamic State regards Shiism as innovation, and to innovate on the Koran is to deny its initial perfection. (The Islamic State claims that common Shiite practices, such as worship at the graves of imams and public self-flagellation, have no basis in the Koran or in the example of the Prophet.) That means roughly 200 million Shia are marked for death. So too are the heads of state of every Muslim country, who have elevated man-made law above Sharia by running for office or enforcing laws not made by God."
Shia and Sunni are allied and fight in the same cause even as they slaughter each other on the ground. Iran supports ISISin Lybia and Boko Haram in Nigeria even as Persian aircraft bomb ISIS in Iraq. But when the Infidels are all dead or converted the Sects of Islam will fall upon each other with a zealousness bounded only by the limits of resources necessary for Jihad to continue. In an Islamic world the Shia and Sunni will divide all up in the areas they can defend and the smaller sects will be pushed into enclaves in inaccessible places. And there are actually more than just two sects. There are Alawites, allied with the Shia but NOT Shia, and the Druzes and many others. And there are the Sufis which are more ambiguous in that they are present in the other sects as the mystical Moslems and something approaching philosophers in Islam. All are ultimately anathema to each other but allies against the infidels.