This is just an UNICORN expressing his highly biased opinion. I think you would probably agree that many people outside of faith are Good people, and reflect sound ethical and Moral judgement. Personally I value the rights, freedoms and happiness of others much more greatly than the edicts of a supreme being. The concept of a "lawgiver" is not a necessary part of the equation.
Universally, moral and ethical standards are ingrained in people despite of logic and reason. Ethics and philosophy teachers will ask first year students if it is wrong to have sex with their sister if they are having sex for non procreative purposes, would not and could not conceive, and removed God from the equation. This is such a standard that everyone, atheist, agnostic, Christian, Muslim, Daoist, etc... all agree should not be done, even when all factors are removed. Maybe there is no conscious "Rationale" reflected in this sentiment but this speaks to the power of the human mind to observe rules based on their practical value in a social system.
Ultimately, even in a church, the rules of morality do not come from a lawgiver, but from the pressure of the society that the churchgoer subjects themselves to. There is great danger in this perspective in my opinion, because the prospect of utilizing empathy for a basis of a system of personal or universal "justice" is taken out of the equation. The basis of morality existing in the realm of dogma is a most threatening prospect indeed. I think even Devout Christians could understand that, and indeed this is the reason that the protestant branches of Christianity sprouted from the Catholic Church.
It is far better, I think, that one is not murdering, raping and selling slaves because he honestly finds it distasteful than to believe the only thing stopping him is that God told him not to. Especially when the christian God never told us not to sell slaves in the bible, and requires a man purchase a dowry for a raped woman, and then marry her.
Deuteronomy 22:28–29