Right, and they wouldn't have said "God bless America," but the current common morality of America, both eschewed by those in power and common citizens, is driven in no small part by Christian values and beliefs. It's not the only value, but it's a bedrock of one of the main political parties and an important pillar of the other.
I guess my point is that the distinction between a terrorist from Syria and a military escapade from America is largely a matter of dressings and trappings. And in terms of raw body count, one side is clearly ahead of the other. That the same side doesn't quite profess to wanting a theocratic state doesn't invalidate the reality that much of western society is still Christian in nature, for a lot of people, from the influence of the 10 Commandments, to church attendance, to common and shared values driven by interpretation of church doctrine.