Earlier quoted context omitted.
You're raising the spectre of artificially nonfungible conditions, and ignoring power differentials between employers and employees, as well as game theory leading to non-optimal equilibria.
I don't understand what you mean when you say that I am "raising the spectre of artificially nonfungible conditions"; I described a possible situation, and asked whether you agreed that it was possible that non-compete bans could be 'anti-employee' per your definitions. I agree that I am ignoring many things, as this is a limited discussion, and I am only addressing the impact of a law on a single employee, and its e…
Secondly: my second point answers my first.
Markets don't manifest in individual transactions, they manifest as the emergent behaviour of multiple transactions. As others have noted, setting bounds to what can be traded away has proven necessary, empirically, to avoid winding up in a highly non-optimal equilibrium point.
If you're interested in ethical ramifications, I recommend two excellent works on the topic: A Theory of Moral Sentiments and An Inquiry into the Nature and Causes of the Wealth of Nations.
Even that treatment is unsatisfactory as it neglects considerations of short-term vs. long-term trade-offs.
Your example is contrived in that it essentially poses a Sophie's Choice: give up condition of long-term viability A or because of my superior position in establishing and enforcing terms, give up condition of long-term viability B.
The optimum condition would be for no artificial constraint on A or B imposed by the employer.