Non-competes under U.S. law are neither all good nor all bad. They have their legitimate uses but these are the narrow cases and not the norm.
For example, you sell a business to someone who pays you a big premium for your goodwill value usually tied to the value of the customer base. It is entirely fair that, having taken the money in exchange for the sale of your goodwill interest, you not be able to turn around the day after the close and effectively steal it back from your buyer by setting up a competing business and conducting raids to get back your old customers. A reasonable restriction on your ability to compete in that case makes eminent sense and is not in any way unfair.
So too if you exit a professional practice and get bought out. Same principle. You get paid for the goodwill value and you should not be able to capitalize on the payment and simultaneously raid the goodwill of your former practice by competing against it. Fair and reasonable even though it restricts you in your livelihood.
Thus, even states like California, which basically ban the use of non-competes in an employment context, will fully enforce them in the situations noted above.
On the bad side, non-competes tend to operate unfairly and to burden ex-employees by preventing them from engaging in their normal livelihood even when they have been paid nothing for the privilege. Many jurisdictions do enforce them in that context and the only way to challenge them is to argue that they are unreasonably broad, which (if fought out) takes a tidy six-figure sum to prove in court.
So, yeah, all jurisdictions should adopt the California rule that largely bans non-competes in an employment context. But I don't see this happening anytime soon.
In the meantime, as an employee, you should try to avoid these if you can, negotiate to be paid for any non-compete if you have the leverage, or, if you have no choice, live with them as best you can until the law comes to a better place. As long as the law enforces them, you are sometimes just stuck.