There is a difference between thinking that something is important and thinking that something expresses a deeper physical reality. That earth, wind, fire, and water are primary is a value judgment--that everything else is made of one of these four elements is a (false) factual assertion.
The same thing with natural rights. You might think it's important not to kill people, no matter if they're American or not. That's a value judgment. But to assert they have a "natural right" not to be killed--that's a factual assertion. If you do kill them and do an autopsy, you won't find any "natural right" in there.
I don't link the notion of a "natural right" to "expressing a deeper physical reality." That's your definition. In any case, I stand by what I said: respecting human life should be considered part of our values. It was a foundational idea at the start of our country.
The same thing with natural rights. You might think it's important not to kill people, no matter if they're American or not. That's a value judgment. But to assert they have a "natural right" not to be killed--that's a factual assertion. If you do kill them and do an autopsy, you won't find any "natural right" in there.