It's also power asymmetry. Some people just can't afford to NOT sign a non compete. That's why laws and regulations are needed to protect the poor.
Last time I had a decision to make on a non-compete, I did consult with a lawyer and he basically said there are no guarantees, but generally a non-compete cannot be enforced if it prevents you from earning a living.
Edit: the article implies that places like McDonald's do this. I worked there (albeit years ago), and at that time it was not true. We would have been rightly laughed at if we asked for a non-compete on a minimum-wage job like that. It was hard enough to hire people who were reasonably well-groomed, punctual, and energetic. We would not have added unnecessary barriers like that.
https://www.foodandwine.com/news/fast-food-non-compete-agree...
Define "years ago". Improvements to technology over the past few decades have disproportionately eliminated low-skill jobs, leading to an increasingly desperate job market for low-education workers. Desperate people don't have the luxury of refusing a contract based on something abstract like a non-compete. Hell, if it were legal for McDonald's to pay their line workers exclusively in McDonald's Fun Bux rather than dollars, they would still have a surplus of applicants. Desperation is the ultimate enemy of rational decision-making, and at the end of the day poor people still need to eat.
Also there are (or at least were) fast food restaurants making their employees sign non competes. Jimmy Johns had their sandwich makers on noncompetes until 2016 [0].
0: https://www.cnbc.com/2016/06/22/jimmy-johns-drops-non-compet...