It is an utterly facile point with little bearing on reality. The United Nations has reams of documents outlining what "human rights" are. Like, um, this one. The Universal Declaration of Human Rights has a couple of claims that I don't personally agree with, but this is what the United Nations says that they're backing in terms of human rights.
As a non-binding treaty, and instead only as a declaration. Its main power comes through the fact that it is accepted as part of customary law...meaning, it is law because many nations consider it to be custom. It's at the whim of the international community; if suddenly, the major world powers decides they don't want this declaration, then it loses even customary power.
According to Wikipedia, Iran have actually refused to abide the UDHR, saying it is incompatible with Islam, and instead, 40 nations have instead adopted a rival declaration,
the Cario Declaration of Human Rights in Islam. And, also, according to Wikipedia,
there are 193 widely recognised sovereign states and 203 sovereign states alltogether. If 20% of the world refuses to abide by this declaration entirely (I think there is some overlap between the two declarations), then I pretty much assume this declaration doesn't have the force of consensus, and may not even have any customary power whatsoever (I say "may", because I don't know how many nations have to agree to 'customary law' for it to be 'customary law').
I actually believe that the UHDR and Islam are compatible, and thus disagree with Iran here...however, we may have different interpretations of that declaration. Who's going to decide which interpretation is correct? Again, the international community, and the international community does not always have the best interest of human rights at its forefront. "National sovereignty" comes to mind as a major part of international law that must be defended and protected, even at the costs of human rights.
It is true that the United Nations has
a goal of promoting human rights. But it also have other goals too. It is, primarily, a forum for international cooperation, and quite frankly, there are a ton of other issues the international community has to worry about.