it would be in the interests of the dark, backwards and uncivilized forces of islam to try to create a holy war between christians and muslims, and all evidence seems to be that they're essentially delusional on the matter. they think the west is christian.
but, the west is not and never has been christian, we are an enlightenment society built on rationalism and science, and it is important that the response is framed in terms of secularism v religion, and not in terms of christianity v islam.
so, don't let them frame the issue that way.