Second, dignity is fungible. The Council [The President's Council on Bioethics] and [the] Vatican treat dignity as a sacred value, never to be compromised. In fact, every one of us voluntarily and repeatedly relinquishes dignity for other goods in life. Getting out of a small car is undignified. Having sex is undignified. Doffing your belt and spread- eagling to allow a security guard to slide a wand up your crotch is undignified. Most pointedly, modern medicine is a gantlet of indignities. Most readers of this article have undergone a pelvic or rectal examination, and many have had the pleasure of a colonoscopy as well. We repeatedly vote with our feet (and other body parts) that dignity is a trivial value, well worth trading off for life, health, and safety (Steven Pinker)
But voluntary relinquishments of dignity are not the point. Involuntary ones are. The fetus does not voluntarily choose to relinquish life. The worker in the developing world is not voluntarily denied a living wage. The child living in a slum does not voluntarily choose hunger. The handicapped person does not voluntarily choose to be discriminated against. The nursing-home patient does not voluntarily choose to be treated inhumanely. The torture victim does not voluntarily choose physical agony. The victim of genocide does not voluntarily choose death.
This is quite different from getting out of a small car. In Catholic social teaching, human dignity has little to do with occasionally looking "undignified" or "silly." It is about the inviolable value and worth of every human being, who is created by God. But this foundational concept in human rights is not something that appeals simply to Catholics, or Christians, or even simply to believers. As Pope Benedict XVI said in his recent speech to the U.N. General Assembly, "Human rights are increasingly being presented as the common language and the ethical substratum of international relations. At the same time, the universality, indivisibility and interdependence of human rights all serve as guarantees safeguarding human dignity." (James Martin, SJ)
Hat tip to Didymus from the Catholic Answers Form that pointed me to the article.
Its hard for me to imagine why anyone would have a problem with human dignity being a central concept in ethics.