Morality is about having the right preferences, as rationality is about having true beliefs.

I understand what it would mean to have a true belief, as truth is noticeably independent of belief. I can be surprised, and I can anticipate. I have an understanding of a physical world of which I am part, and which generates my experiences.

It does not make any sense for there to be some "correct" preferences. Unlike belief, where there is an actual territory to map, preferences are merely a byproduct of the physical processes of intelligence. They have no higher or divine purpose which demands certain preferences be held. Evolution selects for those which aid survival, and it doesn't matter if survival means aggression or cooperation. The universe doesn't care.

I think you and other objective moralists in this thread suffer from extremely anthropocentric thinking. If you rewind the universe to a time before there are humans, in a time of early expansion and the first formation of galaxies, does there exist then the "correct" preferences that any agent must strive to discover? Do they exist independent of what kinds of life evolve in what conditions?

If you are able to zoom out of your skull, and view yourself and the world around you as interesting molecules going about their business, you'll see how absurd this is. Play through the evolution of life on a planetary scale in your mind. Be aware of the molecular forces at work. Run it on fast forward. Stop and notice the points where intelligence is selected for. Watch social animals survive or die based on certain behaviors. See the origin of your own preferences, and why they are so different from some other humans.

Objective morality is a fantasy of self-importance, and a hold-over from ignorant quasi-religious philosophy which has now cloaked itself in scientific terms and hides in university philosophy departments. Physics is going to continue to play out. The only agents who can ever possibly care what you do are other physical intelligences in your light cone.