[Cavernio]

Fido: So because, as a kid, I didn't know that the world was made up of atoms which are then made up of electrons, neutrons and protons, and because now I don't know what those things are made up of, and because the majority of people have no idea either, so we can clearly perceive things about the world differently, what you're saying means that what atoms are made up of is, in fact, subjective.
But you don't think that, you would say atoms and their constituents are objective, just like math is.
And I agree; atoms are objective. And in regards to morality, I don't think that just because I might have a different view of the morality than someone else, doesn't mean that morality is subjective.
Like, pretend we're all fish or dogs or something who have a very limited intelligence, some animal that clearly cannot grasp the simple idea that 1+1=2. That doesn't mean that 1+1=2 isn't true.
And those aliens of that civilization, when being murdered, would still have their lives ended. (Thievery is much less clearly wrong, so not going to go there.)

Rubix: So using the evolutionary definition of morality you have, I agree up until "However, what we'll agree upon as being the "right" choice depends on our utility profiles, and everyone's profile is going to be slightly different."...which is arguably when you switch from morality being objective to it becoming subjective.
For the sake of argument, what if what I perceive as the best choice for me/my situation/even the world!, in fact leads to the total destruction of the earth, putting back evolution in our little part of the universe by billions of years? How is that choice of mine still subjectively the best thing? Clearly there was an objectively wrong choice that I had made, even if I thought it was right, and even if I think that the choice is subjective.

Enh, whatever I said above, this is the only point that really matters: Maximizing the utility profile of everyone and everything that exists and may exist, whose existence is such that it can experience bad and good, is being moral. And it is objective.