No it doesn't. You can get different results from using different foundations of natural law, but depending on the foundation you use, the results work out consistently for whichever foundation you chose.
But I would argue that that requirement is why societies and governments are formed, and we surrender (or "balance") our absolute natural rights for the benefits derived from that man-made balance. That balance is not part of the natural law, but it's compromise by men to lead in order to lead less nasty, less brutish, less short lives.
You need to read more natural law. Locke is pretty good for starters.
Which one is slavery? Is that only wrong because we say it's wrong, or is it inherently evil?
Oh, depending on your foundational assumptions, it's inherently evil, but often people who grew up with it being acceptable may not be aware of it until it is pointed out to them. In other foundational assumptions, it is not evil, but is instead perfectly consistent with the laws of nature.
But while we're on this point, the concept of a "solid" anything doesn't exist in physics or in philosophy. Something I have learned is that Schrödinger's Cat like states exist everywhere and everywhen.
Doing Vector Math taught me that a number can be three numbers, or even a matrix. Calculus taught me that a number can be a function, and may not have any single state condition, but an infinite number of them, with in ranges.
"Solid" answers often depend on a whole lot of specific factors of interest.
So basically you're saying that there is no absolute moral truth, merely societal constructs.