If "X is good" was simply an empirical claim about whether an object conforms to a person's values, people would frequently say things like "if my values approved of X, then X would be good"....

If that is your basis for a scientific standard, then I'm afraid I must withdraw from this discussion.

Ditto, if this is your idea of humor.

what if "X is good" was a mathematical claim about the value of a thing according to whatever values the speaker actually holds?

That's just silly. What if c = 299,792,458 m/s is a mathematical claim about the speed of light, according to what the speed of light actually is? May I suggest that you don't invent unnecessary complexity to disguise the demise of a long deceased argument.

No further comment from me.