The basic moral principles which (used to) be the foundation of law are universal, the exact opposite of any kind of narrow sectarianism.
Laws against murder, assault, kidnapping, theft (which includes robbery, embezzlement, etc), lying (which would include lying under oath, slander and so on), rape, molesting children, sexually abusing animals, animal cruelty, adultery, sodomy, and so on are all based on religious principles.
You don’t like these laws? I realize that laws against adultery and sodomy have gone by the wayside (except in the military code of justice) but most conservatives will agree that the Lawrence vs Texas decision legalizing sodomy was a very bad decision.
Some of these are based on religious principles ("sodomy" for instance); some are not. The most basic laws are simply what is needed to run a civilized society and were in the earliest attested law codes. And then there is the question of ethics, which can and does stand apart from religious principles. Our basic standards for ethical behavior and for the concepts of our government stem from classical (read: pre-Christian) philosophers. For instance, Plato's "Crito" is one of the most concise, and moving, explanations of the concept of the rule of law that you will ever find.
You don’t like these laws?
Some I don't like. I do not care for government intrusion into the private lives of consenting adults based on the religious beliefs of a subset of Americans. It bothers me not at all that two guys down the street might be having buttsex, as long as I don't have to watch them do it.