If there's no Supreme to whom all Authority belongs, maybe… but if there is then moral authority belongs to him and he defines it.
Now, if that authority is unchanging, then so is his standard of morality, and if that be the case then morality is objective.
On a side note.
In my observations of this debate and how the culture and media have dealt with a the growing uncertainty of the Neo-Darwinian narrative, I am seeing more and more acceptance of a super-natural explanation.
The scientific community is venturing into Meta-Physics and invoking and number of Multi-Verse theories.
This, in my opinion, has opened the doors for the POP-Science shows like “Ancient Aliens”.
If you watch that show, they rarely address the question of evolution and infer that “knowledge” came suddenly.
The show is surprisingly popular.
I see it as an “out” for a culture that has been conditioned to reject religion and creation in particular.