I have the feeling, especially being from Minnesota, or even Michigan, with the large Islamic population, it is easier to conceive of seeing evil in your own government, than a radical religion that is committing terrorists acts around the world. One you can sound off about, and not feel all the threatened by, where as the latter, is more like a real bogey man that you don't feel safe or able to combat. Really, I think the folks that believe this stuff, do, because it's easier than being terrified of something they have absolutely no control over, and also the not knowing what is to come if they believe terrorists did this. It makes them feel more vulnerable if it is from outside the country.
Doesn't really make sense to people who don't buy into it, but to them, it's easier.