So I heard lots of frustration in comments around the concept but little commentary on the legality of it. Not a lawyer but do have extensive experience in HR and employment law:

Companies can put anything they want in a policy. That policy may or may not be legal. A policy that is not legal may open up lawsuit opportunities against the employer, but because most violated employees simply complain on message boards on the Internet instead of learning their rights, the policies and violations continue.

In this case, it has been well established that companies cannot limit your employment opportunities outside of work, unless you have a contract that specifically includes it AND you are provided consideration (payment or something of value in a legal contract) for this concession. You can be legally and simply terminated if you are doing non-company work on a company device, if your performance is not meeting standards, or if there are any conflicts between your employer and your other jobs, hobbies, etc.

There have been a lot of cases and laws in the last 5 years massively limiting the scope (because employers will always push any advantage as far as they can until they are regulated, legislated or outlawed) of “non-compete” clauses in job offers and policies. 10 years ago every employer was throwing these into employment contracts, some employees called them on their bullshit and now you don’t see them as often–but there are definitely still companies (especially small or new) who don’t have anyone who knows what is legal in this area and just make shit up. The only real holding power a non-compete has is if you have mission-critical information or trade secrets and again they must then receive consideration/payment for this concession of their ability to earn income elsewhere --and 99.9% of employees outside of C-suite don’t.

If you’re interested in learning more about employment law, trends, or have questions, check out my new community I created last week “Ask HR”:

https://lemmy.world/c/ask_hr