Irrelevant to this discussion, yes.  False?  No.

Even so, I agree.  Being an American is one thing.  Being Buddhist, Mormon, Catholic, or Protestant is something else entirely.  One can be fully any of those and still be fully American.  

Still, utilitas raises a serious question that we ignore at our peril, namely, whether a fundamentalist belief in the Quran is compatible with assimilation into Western culture.  I tend to doubt it.  Consider the irreconcilability between our Constitution and Sharia law.