One sentence that throws the problem of evil out of the window.

[Whateverist]

As a practical endeavor, morality can be argued objectively based on shared valuations.

Regardless of whether or not you and I share a valuation, rape is what it is.  This is the objectivity being refered to in objective morality.  Not that we share a valuation, but that any agreement or disagreement between us is not with reference to what is being observed.  It;s neither of our opinions that rape is harmful.  It isn't made more or less so by us thinking that it is or isn't, or by one of us thinking that it is and the other thinking that it isn't.  It;s important to note that, otherwise we'll end up with pages and pages of the shared opinion trap, lol.  

For me this is just the difference between my willingness to be ruthlessly practical in implementing justice, where I hang back from codifying moral experience out of regard for the possibility of a difference in subjective experience which I just can't be sure of.

You know nature is pretty good about diversifying its portfolio. In general, sickle cell anemia is an undesirable condition but because of it, in the face of a malaria outbreak, at least the population pulls through and more sickle cell free individuals will be born to enjoy the good times. It wouldn't shock me to find that some individuals are morally blind, only able to regard their fellow human beings practically as useful or detrimental to their ends. Such individuals, though pariahs in the good times, might likewise pull through keep the population going in circumstances where cooperation wasn't getting it done. Purely speculative on my part but it is why I don't assume we are all the same morally.

So perhaps what you're calling objective morality is what we normals acknowledge as morally permissible or not.