I’m not sure what prompted this thread but here’s my general argument against atheists regarding morals:
Thesis: Secular Humanism is oxymoronic. Why?
In meta-ethics morality is either Realism or Anti-Realism. That is objective facts or subjective desires, relativism.
The only moral theory compatible with naturalism and materialism is moral anti-realism. It means there are no universal moral truths independent of cultural relativism. Moral right and wrong behavior is dependent upon the culture’s customs. Even though these customary morals can evolve and change the notion of moral progress is meaningless. Why? because you cannot have progress without an objective thing (moral objectivism) to measure/gauge the progress against.
If morals are dependent upon cultural customs and cultures tend to differ in custom the notion of a Universal morality is also meaningless. Human Rights are dependent upon the moral Universalism.
Secularism is a metaphysical system which holds to the belief that nature and materialism is all there is. Ego the nature of meta-ethics is moral anti-realism.
Humanism OTOH is a meta-ethical belief system which holds to the belief in the Universal dignity of human life and human rights…irregardless of cultural customs. There is a universal moral truth. Ego the nature of meta-ethics is moral realism.
How can a belief system calling itself Secular Humanism be both moral anti-realism and moral realism at the same time without creating an oxymoron? The simple answer is, it can not.
So for the atheist morality is akin to aesthetics. An atheist arguing that his/her way is the correct moral way is like arguing his/her favorite flavor is ice cream is the correct flavor everyone else must universally adhere to, or arguing their table place settings is the universally correct placements everyone else must/should adhere to. Atheists are being internally hypocritical anytime they engage in moral debates implying a correct morality and moral progress. Why? Because if there is such a thing as moral progress then it logically follows that his/her Naturalism and Materialism is false.
If Materialism is false then some other metaphysical reality must be true. It could be theism, ancestralism, or something else…but it is not the monism of naturalism and materialism. Reality would have to dualistic for human rights to have any inherent debatable validity.
So which is it? Which is it for you, the monism of materialism were there cannot be such a thing as factual moral progress, human rights, or an inherent human dignity - or is the nature of reality a dualistic one where morality is Real and so to are human rights, and inherent human dignity? The choice you make will always/eternally be a choice made by faith/Faith.