Full transparency, even though I identify as atheist, I must admit to agnostic. I don't know what I don't know. Neither do the theists, which is why I ID as atheist.
I prefer no discussions of god for that reason.
Do no harm is exactly the objective morality, unlike the moral relativists from the utilitarian (im)morality of the greater good. The greater good is for slaves to exist to serve the slave's owners.