What, ultimately, is the basis for morality? Many people argue that some things are self-evidently wrong, like torture and murder. No need to invoke the Ten Commandments or any religious tradition. Some things are just wrong. Period.
This is a respectable idea with a long lineage. It’s the argument of Natural Law. All people are born with a natural sense of right and wrong, and it is only later, through vice or degeneration, that some can no longer correctly tell the two apart.