I don't know why you are bringing up hedonism. It is bad to kill even if you enjoy it; so if morally good means what it is good to do, as I say, it will be morally bad to kill even if it is pleasant to someone.

So what is your theory? That the morally good is the morally good? Weren't you criticising that approach?

"The morally good is the morally good" is vacuous.

"The morally good is the good" is subject to counteraxamples.

The fully intersubjective but non-objective theory of meaning that you are suggesting is also false, since if everyone all at once agrees to call all dogs and cats "dogs", that will not mean that suddenly there is no objective difference between the things that used to be called dogs and the things that used to be called cats.

That is only true if you equate "wrong" with not capturing all the information. But then we would always be wrong, since we never capture all the information. There are languages where "mouse" and "rat" are translated by the same word. Speakers of those languages are not systematically denuded.

"Dog" means something that has what is in common to the things that are normally called dogs. Notice that this incorporates inter-subjectivity and convention, since "things that are normally called dogs" means normally called that by normal people. But it also includes an objective element, namely "what is in common."

That's rather redundant, since the idea that new sages of "dog" shoudl ave something in common with established ones is already part of the norm.

Just as it is not too difficult to see that dogs have some objective features that distinguish them from cats, good things have an objective feature that distinguishes them from bad things: good things tend to result in things desiring them, and bad things tend to result in things avoiding them.

I would say that you have the casual arrow the wrong way round there.

Also, you are, again, using "good" in a way that leads to obvious counterxamples of things that are desired or desireable but not morally good.

Now that tendency is not complete and perfect, especially because of people making mistakes. So occasionally someone desires something bad, or avoids something good. But the general tendency is for good things to result in desire, and bad things to result in avoidance.

If you could work out the difference between the mistakes and the norm, you would have a non-vacuous theory of what "morally" means in "morally good". However, I don;t know if you are even trying to do that, since you seem wedded to the idea that the morally good is the good, period.

We then call the things we tend to desire, "good," and the things we tend to avoid, "bad," but actually the good things have nothing in common except that we are desiring them, and the bad things have nothing in common except that we are avoiding them.

If you want the word "good" to do all the work in your theory of moral good, yo would have that problem. If you allow the word "moral" to do some work, you don't. The morally good has features in common , scuh as being co-operative and prosocial, that the unqualified "good" does not, and that is stil the case if the good is not an objective feature of the world.

And that answer does not make sense, unless the good things have something objective in common in addition to the fact that I desire them.

You don't need objectivity, intersubjectivity is enough.