I appreciate that this is a topic of discussion, whatever defects the author's post contains, both explicit and tacit.
Some commentary:
1. Ethics is the practical science (in the broader classical sense, not the narrow empirical sense) of right action. But what determines right action? I'll make a stronger and more complete claim: it is the study of human nature, its ultimate end, and the principles that guide us there. Ethics is, therefore, about the principles that underpin the good life. Without its grounding in human nature, and without an end inherent to human nature, there is no ethics. An action's goodness can only be measured in relation to human nature and an end. Anything else is arbitrary and meaningless, hence the widespread and childish conviction that morality is just some set of made-up rules, or perhaps some otherworldly feeling of a gnostic variety. Ethics, morality, and virtue are not external things that we can sometimes appeal to and sometimes not. They concern our condition as human beings at all times and every single decision we make.
2. What the author is talking about when he calls ethics a skill is really personal morality and virtue. Am I a virtuous person? Do I do what I ought or do I habitually choose to do what I ought not to? Ethics helps us clarify our understanding of the underlying principles governing morality, but morality and virtue as such involve their concrete application. Prudence is nothing but the ability to discern what the right decision is here and now and in this situation. It is effectively the skill of applying general moral principles to particular circumstances.
3. A good society requires good members. As bad as collectivism is, this is one reason why libertarian hyper-individualism is also bogus. We are social animals. Our good is not sealed off from the good of society. Our personal immoralities don't just affect us; they affect the society we live in. We are our morality, as it were. If you're a crappy person, you drag the condition of society down. You have a moral duty to be good, and since you are a social animal, that also means you are obligated to be just and even charitable as prudence requires.
In short:
- Ethics is the scientific study of the good life and the end of the human person.
- Morality is the rational quality of our concrete, freely chosen actions.
- Virtue concerns the internal habits that give us the power to act rightly.
- Prudence (the first of the so-called "cardinal virtues") is the practical skill (the "art") of applying ethics to daily life.