Slightly different perspective where how I can see this applying, with regard to our decadent society - a missionary to Dearborn MI spoke at our church last week and she said this, that because most Muslims live in countries were Islam is the official state religion, they look at America the same way. Since America is called a "Christian" country, most Muslims think that CHRISTIANITY sanctions the ridiculous behavior that they see in our various forms of media, the fact that our mainline denominations are allowing gay clergy, etc. They believe that American culture is the personification of Christianity, so they hate both entities and see them both as a threat to Islam.
Does that give them justification to murder? Of course not - more like an excuse. But for missionaries here and elsewhere trying to reach Muslims, it sure puts up a big misconception that has to be broken down.
The overwhemling number of Muslims, like the overwhelming of westerners, are prisoners of their own historical and social perspectives, which prevents them from accurately assessing the danger (as this applies to of Islam) or the merits (as this applies to western society)of the opposite culture.
Muslims simply don't understand "freedom" as we do.
Westerners, shackled by political correctness, simply view Islam as just another religion and the terrorists as abberrant renegades.