The fact that the Islamic State kills other Muslims is often proffered by Barack Obama and others as a sign that it is itself not Muslim. In reality, the fact that the Islamic State kills other Muslims is a sign that it considers itself the arbiter of what is true Islam and what isn’t, and considers itself to have the authority and right to execute Muslims whom it considers to be heretics and apostates.
“ISIS’ Egypt branch executes 100-year-old cleric,” Al Arabiya, November 19, 2016:
Ansar Bayt al-Maqdis – ISIS-affiliated extremist group in Egypt – has released images purporting to show the execution of a 100-year-old man.
The group, who rebranded as ISIS-Sinai when they pledged allegiance to the extremist group holding swathes of Iraq and Syria, killed Sheikh Sulaiman Abu Haraz after kidnapping him earlier.
Abu Haraz, considered one of the symbolic Sufi clerics and elders of the Sinai Peninsula, was taken by the group from in front of his house in Arish city under gun point.
ISIS-Sinai accused the elderly sheikh of “practicing witchcraft”.