There’s no possibility or need for morality to be universal, and societies have improved their ethics many times throughout history. Your take is nihilistic and presupposes that moral progress isn’t possible, even though we’ve seen objective moral progress many times.
Morals / ethics change of course. However that is not objective progress, only subjuctive. You think it is objective because you agree with the new system. Slave owners of the past would call it a regression that they can't live their lifestyle. Of course I agree with the new standards (at least here) and so am glad they can't.
edit: yes, nillistic - but sometimes you have to go there
Just because it’s subjective doesn’t mean it’s incorrect. The slave holders were wrong, you and I are right. Less human sacrifice in the world is a good thing, and we shouldn’t require a perfect ethical framework before we act ethically, because some real things aren’t reducible to objective logic or perfectly consistent ontologies.
