So far historically it was "they're not Christians", then it was "wrong location" (cause they wanted the land/resources), then it was "they're not the right race", then it was "wrong economic system", and now it's "wrong culture"; what's next do you think?
EDIT: By justifiable I don't mean it's actually justifiable, I mean most people will consider it justifiable.
i think that there's still plenty of mileage left on the good old fashioned "they're terrorists" excuse that worked this time around.