Christians were regarded as separated from society and therefore destructive of the Greco-Roman way of life.
When I really have to push and grope and scratch and claw to make a story work, that's a telltale sign that maybe something conceptually isn't right.
Their plan is to return the entire world - not just the Middle East - to the days of the caliphate and either convert all of us so-called infidels into born-again Islamic believers or kill us.

