The States have 50 different approaches written into their laws on how to deal with non-competes. Some ban them entirely, while others curtail their scope or shift the burden to employers to justify them, and many do not regulate non-competes at all. A rule by the FTC that preempts the laws of every state for all non-competes regardless of scope without any specific statutory authority is the wrong approach.
The FTC is justifying this under Section 5 of the FTC act, which in relevant part prohibits "unfair or deceptive acts or practices in or affecting commerce." This kind of wholesale preemption of state law regardless of context seems like an awfully big change for such a broad and vague statute. Underscoring this point, the FTC has not historically used Section 5 in this way.
Expect to see this challenged in court.