Morality is a word symbol to describe as aspect of reality. What is being described, is objective, they are actions. The only subjective aspect is that it is consciousness that discerns. Much like truth is a word symbol to represent reality and existence. Truth doesn't exist in itself, nor does morality. "The truth" is a universal concept, it emcompasses everything that is, much as reality and existence does. They are grouping-concepts, universals, to group everything together and represent it as a word symbol. The word universal is a grouping concept, uni-verse, turned into one. The universal concepts of truth, existence and reality are representative of the objective universe. They are not things unto themselves as particular primary substances (Aristotle's metaphysics). To claim that truth is subjective would be making the same mistake as claiming morality is subjective. Just because they don't exist int themselves does not mean they are not valid referential concepts about an understanding in objective reality.
Truth and morality are not determined based on subjective whim, wants of wishes. They are objectively determined.
These words describe aspects of reality. Reality is objective. These terms can be objectively understood in reference to reality.
“but if we don't tax, the absence of the police will lead to an increased overall rate of suffering”
This is irrelevant to the actions created into reality, that of taxation, and that it is a wrong. Just because another seeming problem arises from the removal of a wrong, does not invalidate the objection to the wrong and "magically" make the wrong a right. Even if something is less wrong, its still wrong. Right and wrong, good and evil, describe the diversity, variability and multiplicity of actions in reality, along a spectrum, a scale, in degree of application, which I called dualistic conceptual framework. The polar ends are not realities, but ideals to use to value and discern the relative variability within the spectrum. In terms of this example, the solution is not to allow taxes, or a centralized authoritarian police force, but for people to develop personal responsiblity and evolve consciousness to understnad hwo to control themselves, to self-govern themselves, and respect the conceptual ideal of what is right and wrong through an understanding of the reciprocal cooperative optimization of survival together, which means not harming others. Nonaggression, nonviolence.
Our objective actions and their affects on others, the consequences, can be understood. They are objective. This is morality.
Philosophical divisions miss the point and construct frameworks/models in a rigid manner so as to deny the other models. Then they try to argue which one is "best" in their stubborn attachment to a definition of their particular model, rather than try to incorporate what is valid from each to form a holistic accurate understanding of reality.
“The limits of my language mean the limits of my world.”
– Ludwig Wittgenstein
They can't see the reality or morality clearly because they are blinded by limiting definitions of morality as defines by specific models, rather than seeing things more clearly by evaluating the merits in all of them through an objective understand of reality. The definitions are attached to, and they seem to be trapped by them. They need to take what is valid in all of the models, and drop stubborn attachment to one or the other as the "only" valid model to use. You seem to be doing similarly, by trying to merge what is valid in either. But, morality is not subjective, it is objectively defined by our actions, not constricted models that lack inclusion of other valid understanding. The models need to be expanded upon, and not attached to.
As I said, the subjective aspect, is the consciousness that is able to discern what action are doing to others. The subjective consciousness wants to be subjectively attached to themselves often, and deny "rights" to others groups that they deem can be excluded from moral violations. Like taxation for the group of citizens. Like slavery for another race. And other justifications for the exclusion of others from the concern of our actions towards them. Our actions are at the root of morality, not who the "other" is and how we view them as different from us. Most moral/ethical philosophers don't get this yet, and are still denying who qualifies as another, not evaluating them as a consciousness being on their own level, both cognitive (thinking) and effective (emotion) differences in degree.
Take care. Peace.
RE: Arguments against objective morality