Since this should be illegal, or at least illegal absent some reasonable compensation for giving up the right to freely seek alternative employment (e.g. a big retention bonus), presumably our politicians offering "regulatory relief" are to blame?
I had a friend who got RIF'd from a software company, and their offboarding paperwork included a 1 year noncompete that tied their severance as the consideration. Essentially, "we don't want you working here, but we also don't want you working anywhere else, either."
I got RIF'd and they included the paperwork signed at offer time for the non-compete. I didn't sign it thinking they would try to force the non-compete after the employment was terminated by them.
It's reasonable if the severance is equal to the pay you'd get over the term of the non-compete. They don't want you working for a competitor for a year? That's fine, if they pay you a year's salary.
However, in my friend's case, she was given the 1-year noncompete in exchange for 4 weeks' pay.
That creates the incentive for someone who wants to switch to a competitor to underperform - so she gets fired and can switch.
Noncompetes, viewed in a vacuum, are lopsided towards the employer by design. Which is why they are (ideally) counterbalanced by increased pay or other concessions to the employee.
Voluntarily agreeing not to compete with a company for some period of time is completely fine as a contract in a free market system. Not interfering in those agreements not only doesn't contradict a commitment to free markets but is actually a logical extension of it: individuals engaging in the system ought to be free to conduct whatever transactions they see fit. Free markets and well-functioning markets aren't coextensive, though, and that's the rub with non-competes.
The article provides one example of Republicans defending the free market, but usually that's the last thing on their minds. (See e.g. how the phrase "everything is bigger in Texas" applies most of all to government.)
