> If in your scenario, I can pay you $3, it's in society's interest I do that and reinvest the rest to increase capital concentrations that are the source of all wage growth, or to hire 5 workers instead of one.

You're assumption is that I'll reinvest the rest into the company, instead of just pocketing the difference myself. If I can sustain myself comfortably pocketing the difference, why re-invest the rest. You're assuming certain incentive structures that don't always exist in the real world.

> No there hasn't. Slavery was a universal institution for much of human history.

Near universal, not universal.

> And this isn't merely theoretical. If in Bangladesh, a minimum wage of $15/hour were instituted, it would outlaw huge swathes of voluntary employment contracts, and would devastate people's economic lives.

Yes and? That isn't relevant to any argument I'm making. I agree that the specific regulations of what contracts can/cannot permit may not all be universal. That doesn't mean that some provisions cannot be universal. As a simple example, a contract between two consenting parties that contracts one to commit a crime on behalf of the other in return for some payment should be universally void, despite both parties consenting. That doesn't require that the list of crimes be universal across jurisdictions. Only that the principle: "A contract between two consenting groups that requires one to act criminally is invalid."

> almost anyone would acknowledge that forbidding two adults from partaking in an interaction they both genuinely consent to a totalitarian infringement of their rights.

Leaving aside my personal opinions on any of these issues, I disagree that this opinion is anywhere near common. There are acts that society considers it okay (and perhaps ethical) to prevent a single person from doing (suicide), and where it is often criminal to help someone (physician-assisted suicide). There are all sorts of acts that all kinds of people want to have the government prevent two consenting people from partaking in (marriage if you're not straight, all kinds of kinks). Currently, some of these things are legal and some are not. "Once you strip away ideological rationalizations" is doing a lot of work for you there. What you're claiming is that "once you strip away <ideological systems with which I disagree> almost anyone would acknowledge <the validity of my preferred ideological system>." Which is vacuous. You have to justify why your system is superior to the others, you can't do that by ignoring them. What makes the world better if we replace a "totalitarian" government, over which I maintain the ability to influence, with a totalitarian corporation whom I can exert no control over? Either explain why that is more just, or why it won't happen.

> Your exploitation arguments are basic on common fallacies held by those without an understanding of economics.

Yet you've not actually addressed them. If you understanding of economics is superior, it should be straightforward to correct me.

> First of all, that's something the government can directly address

They do, by streamlining certain court cases and making particular contract provisions explicitly illegal. You just dislike their solution.

> Lawyers will represent under resourced parties for free because they can earn a commission on whatever the suit wins.

Sometimes, the law isn't perfect. This is especially true if you allow the empowered group to write contracts which include stipulations to, for example, cap their own liability, or require arbitration outside of the court. Things that the empowered group is more free to do under your proposal.

To circle back to the beginning of this conversation, in the US, the freedom of contract you describe is not recognized. So your original claim, that "unions got laws passed that violate the rights of employers" is untrue: the right is not and has not ever been recognized. It is not enshrined anywhere, it cannot be violated because it does not, within our jurisdiction, exist. You can argue that it perhaps should be a right, but it is not widely recognized as one.