RH, I have read your post, and agree that objective statements can be made about moral conditions and decisions, but the morals themselves always link back to subjective decisions. We can, likewise, make objective statements about the perceived outcomes of holding a particular moral position, and even objective statements about how desires arise in our brains. But it still does not get as far as objectively correct reasoning about what morals we should have.

Example of a prudential value statement: "You ought to use this knife" to make sense would assume a desire, e.g. to cut open a coconut, and therefore is making a truth claim about what would fulfill that desire.

Would I then be immoral if I chose to use a hammer instead of the knife? We can't tell without the context. The statement might be information about what works best, or it might be a requirement in a religious ritual such that a moral line would be crossed if I failed to use the knife.

Try to answer this question: How can you come up with the correct objective moral position (what should and should not be) from what is, when we only have at any time a provisional knowledge of what is? Wouldn't we have to know all the scientific knowledge of all the future to show that we have the correct objective answer?