This modern dogma is irrational and untenable. Ethics necessarily are the result of religiously held postulates. For example the Christian has a reason to legislate against murder as moral crime that has a civic remedy, but if one declares all views equally valid, one of those views might be that murder is not morally odious, but preferred in many cases, like abortion, euthanasia for the infirmed or the infidel. Religious commitments underpin moral judgements and moral judgements inform civic law. It is not possible to have a neutral society; neutrality of necessity is anarchy and anarchy leads to tyranny and when the population is bound by the fetters of the tyrants the only rule of law is violence.
Your writing could be a little more clear if you put some effort into it.
If a church is to make the law, for instance in telling the military who is married and who is single among it’s ranks, then which church makes the decision, the Episcopalians or the Catholics?