So where do these inalienable rights you mention come from? And at what point die they emerge? And do animals have them? Are there any circumstances when these rights could be denied?We are getting into deep philosophical waters here. You asked, and I'll answer. I don't necessarily expect you to agree with me, but we can disagree respectfully.
As I said, the idea of a "right" is as I understand it is tied up with the idea of what it means to be human, to be capable of ethical and moral judgement, with a sense of right and wrong. It has to do with living in right relationships with each other as human beings. Who can have the authority to impose such hefty definitions on humanity? That is, I think, a truly God-like power.
I happen to believe in the existence of a Creator who exists ouside of time and the universe. As the Declaration of Independence says, I believe that all humans are "endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness." No guarantee of happiness, only the ability to pursue it, and to enjoy it if you actually manage to find it. Also, I believe that the most important purpose of government is to protect these fundamental rights.
I happen to be a Christian, but this is not an exclusively Christian concept. Ben Franklin was never a Christian, but he did believe in a "Divine Providence". Also, I don't believe that my belief in God in any way gives me any special rights that all human beings don't already have. My beliefs have an impact on how I behave, but that's my burden, not yours.
For those who don't believe in the existance of a divine Creator, then I can imagine that the role of defining humanity may fall on whatever entity is next on the "powerful and eternal" scale. This may be a government, or a society. But governments and societies are still made up of individual people, all prone to their individual failings.
At what point did rights emerge? They have been with us for as long as we have been human, and capable of treating each other as such. We haven't always been good at recognizing them throughout history. As I said, we are capable of moral judgement; That means that we are also capable of moral failing, just as much now as at any other time in history.
Do animals have rights? Not human rights, because they aren't human. I think that we have a responsibility to treat animals in a humane manner, because otherwise we reduce ourselves as humans. But the relationship between a human and an animal is never going to be the same as the relationship between two humans. And, I have yet to meet an animal that is capable of philisophical and moral wrangling. When we humans choose to live like animals, we are at our worst. When an animal lives like a human, that's because humans have taught the animal a few cute tricks.
Are there any circumstances when rights could be denied? They have been, often, throughout history. That, I think, is the very definition of a "crime against humanity". The real question is whether there are any circumstances where a person's rights -should- be denied. There may be times when denying a person's rights may seem to be the most pragmatic or necessary thing do do, in the moment. But I think that it is very rarely the -right- thing to do. It comes down again to that moral and ethical thing. Sometimes the right thing to do is the thing we want to do the least. The only circumstance I can readily believe that taking a person's right to life or liberty may be acceptable may be if that person is already guilty of choosing to take the life or liberty of another by force or fraud. Even then, if at all possible, I want to have a due process of law to hold that power in check.