Not really. The company can add any stupid clause it wants to the contract, but in the vast majority of states which allow NCA at all for employees they're heavily restricted in time and space, and must not prevent employees from earning a living.
In Washington State, NCAs are enforceable if they're "validly formed and reasonable" (Racine v. Bender), although a big issue there is you have to go to court to see whether this specific NCA is enforceable or not. I would guess it's not (because it's completely unreasonable), and Amazon's behaviour is not entirely dissimilar to SLAPP.
edit: in fact, Amazon was essentially told to fuck off in what seems to be a different NCA case: http://www.lexology.com/library/detail.aspx?g=a5cde10f-9ca3-...
> When Amazon learned that Mr. Powers joined Google, it first engaged in discussions with Google about Mr. Powers' employment. Following those discussions, Amazon sought injunctive relief through a Washington state court. After Mr. Powers successfully removed the case to a Federal District Court in Washington, Amazon moved for a preliminary injunction against Mr. Powers to enforce the non-compete restrictions.
> The court denied most of Amazon's requests, and upheld the non-compete restriction only to the extent that it prohibited Mr. Powers, for a period of 9 months from the date he last had access to Amazon confidential information, from servicing any customer as to which he had obtained confidential information* during his employment at Amazon (this restriction was essentially the same restriction as the one Mr. Power voluntarily agreed to upon joining Google).
> […]
> With respect to the validity of the non-compete restrictions, the court next determined that the restrictions were enforceable only to the extent that they sought to prevent Mr. Powers from working with his former Amazon customers. The court also determined, however, that Amazon's attempt to uphold the more general "worldwide" ban against competition — i.e., not tied to specific customers — was unenforceable because it was unreasonable and Amazon failed to show how such a restriction was necessary to protect its business.
(emphasis mine)