I'll remind you, the initial statement you made was "Rights are a fundamental consequence of human nature.", but you're now saying somewhat ahistorical things about slave labor and market economies. Even if what you were saying was accurate, is has nothing to do with how we define rights.
That doesn't make them rights, and it never works.
> You can (and people do) invent and define rights all the time.[...] That doesn't make them rights
Huh?
I didn't say it was. Neither did I say that pi=3 is a right. Please read what I wrote again.
My best guess is that you're trying to make the point that market economies are natural and that the rights we have under them are therefore natural, but this is basically an argument from status quo and it goes directly against what you said elsewhere about healthcare being a right due to government regulations.
And from that you seem to be saying that healthcare is a right due to government regulation, but here you're saying that government decree doesn't make something a right. So like I said, I'm lost.
For another example, the AMA deliberately restricts the number of seats in medical universities. They are empowered to by law. This keeps the number of doctors down, and increases their pay.