Dignity qua human being or Dignity qua persona?

Dignity is the condition but also the consequence of human rights (article 22 UDHR).
But what exactly is dignity? The intuitive definition of dignity would be “worthy of respect”… but why is one “worthy of respect”? Then again, the natural answer would be “because he or she is a human being”.
However, Alain Supiot’s ”The Human being as Imago Dei” seems to offer a different perspective. Indeed, in this chapter, we understand that the notion of personality finds its origins in Ancient Rome and initially meant “the death masks of the ancestors”, the imago. It is only later, with the Humanist/Enlightenment surge that the concept of “personality” was progressively bestowed upon every human being as a result of the King ceasing to be the only incarnation of God on Earth. From then on, all human beings were to be equals – because all made in the image of God- and unique- because God is one. Therefore, all human beings were to have “dignity”.
What it means is that human beings have dignity because they wear the mask of their ancestor, the mask of God. They do not hold dignity qua human being but qua persona, qua Imago Dei; because they represent God on Earth. More importantly perhaps, human beings have dignity because they represent the Christian God. Following the Modern era, law, Supiot argues, has become “the authority that vouches for human identity and symbolizes that they are not to be treated like a thing”. However, despite the apparent objectivity the Law claims to have, scholars, such as Anthony Angie, have also made evident the links between Christianity, natural law and positive law and revealed the embedded eurocentrism of modern international law.
This account of the Christian origins of the concept of dignity is at odds with its traditional understanding and raises issues with regard to the universal project of human rights. I am by no means implying that not all human beings must have their dignity respected. My interrogation rather lies in the consequences that such a conceptualization of dignity can have when applied universally: the refugees’ crisis, treatment of indigenous populations in land eviction cases…. How, if at all, does a Christian-western concept of dignity impact on how the Law understands the dignity of others?