Another way to see morality is as the set of all truths that relate to our behaviours or "what we ought to do" when conscious beings are involved.

My claim is that this set of truths is universal and just like logic, it applies to everyone, everywhere. I am not aiming to show what those truths are; for that, moral philosophers have been discussing for millennia. My claim is, however, that those universal truths of morality exist.

A = "create pointless agony in the world"
B = "remove pointless agony from the world"

If a person can freely choose to do either A or B, are they obliged to do one or the other? In other words, is there any universal truth such as "doing B is the correct thing"?
The same way we justify arithmetical and logical truths based on our capacity for reasoning, our moral intuitions enable us to unveil certain truths such as "one ought to try B instead of A". It is our knowledge of the badness of agony that grant us access to what one ought to try to do.
If one says that it is nevertheless a matter of subjective perception, this reasoning also applies to logical and arithmetical rules which, as I mentioned before, are also based in a subjective capacity.

I find it hard to justify the fact that doing A or B is a matter of subjective perception. In every universe that could ever exist, if agony can be experienced by its creatures, then the rule that "one ought to try B instead of A" will still hold. Moreover, since this would be an objective moral rule, it would still hold even if there were no creatures at all to apply it, just like every logical truth would still apply if there universe were populated only by bananas.

References

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https://pixabay.com/en/learn-mathematics-child-girl-2300141/