Because the logic of counter-terrorism forces them to:
[After the Sep 11 attacks] we generally bought into the Islam angle, and rather uncritically. And by following such monocausal logic to its end, too many specialists in relatively new fields like counter-radicalization concluded that Islam could also potentiallysolve the problem which it caused, creating a negative feedback loop that explains in metaphysical terms why the physical war on terror has no discernible end.
Think of it this way. There are close to 1.6 billion Muslims in the world. All, obviously, have Islam in common, speaking very broadly. But only a very, very small number of those have engaged in acts of murderous violence. We could on this basis instead look for what, other than Islam, explains such instances of murderous violence, as these acts are not exclusive to Islam (in the 1990s, for example, the Bosnian genocide and the brutal Russian assault on Chechnya.)
Instead, we stuck to the monocausal argument, trying to determine what kind of Islam might be at fault, again prioritizing religion over other causes, sustaining Bin Laden’s absurd claim that we (America and the West) were at war with Islam. [link]
My latest piece, for Religion Dispatches.