The Common Law in the US is based off of "religious" morality and values.
For example, not only rape, murder and things of that nature "sins" in Christianty and world religions, but are also "crimes" under "secular" law; with "secular law" having developed or evolved out of older religious and legal systems, such as Roman, Exodus, and so on.
An atheist, for example, can't have any objection to murder, rape and things of that nature except on faith, or on stealing and appropriating those moral values and axioms from world religions (much as degenerate heathen "religions" and cults such as "Satanism" have no morality to speak of which is compatible with that that of law, society and so forth).
So yes, I'd argue based on these facts, state and federal can and should, indeed favor Christianity (and monotheistic, world religion with compatible values) both in public and private over inferior and socially unacceptable trash such as atheism, Satanism and so forth, rather than pretending that such filth and worthlessness is in anyway "equal" to them, when it is decidedly inferior, and has no right to exist it all.