Oh, it certainly is, but the issue is not what we are dealing with—the issue is how the ISIS fighters perceive it.
I’m pretty sure their perceptions are closer to an Albigensian Crusader’s attitude toward Catharism—or even your average Chick tract fan’s attitude toward Catholicism—than some shit-kicking medieval peasant’s grudge toward the old man down the lane who once scammed him for a folk healing ritual that invoked a couple of barbarous names for shock value. Treating religious opponents as devil-worshippers is pretty much built into the basic structure of (premodern, and some modern) Christianity and Islam, whether or not there’s anything to the accusation (though as I note above, the charge is at least as sticky for Catharism as for the Yazidi). The competing presence of a structured religion that’s related closely enough to be uncomfortable but not closely enough to be a heresy per se… that’s a little more distinctive.
I’m pretty sure their perceptions are closer to an Albigensian Crusader’s attitude toward Catharism—or even your average Chick tract fan’s attitude toward Catholicism—than some shit-kicking medieval peasant’s grudge toward the old man down the lane who once scammed him for a folk healing ritual that invoked a couple of barbarous names for shock value. Treating religious opponents as devil-worshippers is pretty much built into the basic structure of (premodern, and some modern) Christianity and Islam, whether or not there’s anything to the accusation (though as I note above, the charge is at least as sticky for Catharism as for the Yazidi). The competing presence of a structured religion that’s related closely enough to be uncomfortable but not closely enough to be a heresy per se… that’s a little more distinctive.