The concept of unalienable rights is a product of the 18th century and inextricably linked to religious belief: rights are inalienable because they are endowed by a Creator. Since modern societies find it increasingly unlikely that there is a Creator, that religious basis is no longer tenable and most of the West (with rising nations like China) now follows some variant of utilitarianism where rights are a convenient and mutable legal fiction to ensure general quality of life.
That's funny. The only place I can think of that specifies that inalienable rights are endowed by a Creator is the US Declaration of Independece. Here's a free hint: not every country in the world uses this as a basis.
Here's what our Constitution says: "Section 11 - Freedom of religion and conscience. Everyone has the freedom of religion and conscience. Freedom of religion and conscience entails the right to profess and practice a religion, the right to express one's convictions and the right to be a member of or decline to be a member of a religious community. No one is under the obligation, against his or her conscience, to participate in the practice of a religion."
Note the wording: "Everyone has the freedom of religion and conscience". It's just stated as a matter of fact. It doesn't need to come from any source. The law regards that as an irrelevant detail that is of no consequence. This is because the law is no place to explore some mysterious rationales for things.
It doesn't matter where good ideas come from, as long as those good ideas are actually upheld. The western society has, as a conclusion to watching strange things happen over centuries, come to the conclusion that freedom of religion and conscience - ability to freely accept and reject religious and moral ideas on personal level - is a good idea, and there's no problem keeping things that way.
Democracy depends on "mutable legal fiction". Otherwise, we wouldn't be able to correct the mistakes that legislators made in the past. Some laws may seem like good idea at time, but sometimes they unfortunately become outdated. And as it happens, basic human rights are good ideas that everyone still agrees are good ideas. Because we've seen what the alternatives are, and they just aren't pretty. Just look at the article.