should be understood as conveying a belief system that is not merely, or even primarily, religious
McCarthy asserts that "Islam’s sharia is a code premised on the principles that Allah has prescribed the ideal way for human life to be lived; that people are required to submit to that prescription; and that Islamic governments exist to enforce that requirement," while the US constitution says we are free to live our lives as we choose.
As is consistent with many of the Islamaphobe arguments within this piece and others, it seems to be based on a high selective and negative-biased reading of the ancient text, rather than the actions and preachings of contemporary Muslims.