The person buying the cloud offerings is not the only customer. Amazon is also a customer, and in their compensation agreement with the vendor (the ex-employee), the ex-employee agreed (presumably) not to work for someone else for some period of time.
Whether or not that should be legal is a different matter. Sometimes if all employers are doing it, it can result in an unfair and unhealthy environment for employees, however, sometimes if all employees can switch jobs willy nilly and take clients with them (especially those with strong relationships with clients), then it can become an unhealthy environment for employers.
If you don't want your clients to switch just because one of your employees switches, don't design your systems to be so reliant on the actions of an individual employee, and don't make your offerings so weak compared to the competition that your clients are willing to switch.
Win by providing better products. Anything else shouldn't be encouraged by the legal system.
...anything else wasn't encouraged by the legal system. The 2 parties (Amazon and employee) entered into a voluntary and disclosed contractual agreement.
Also, sometimes it's not feasible/possible to design a system where clients aren't so reliant on individual employees. For example, in the legal and finance professions, certain key people have so much knowledge regarding certain deals / events, that you can't just swap them out. It is a major investment on the part of a company to train and get someone up to speed on a piece of business, and one way to mitigate the risk of them leaving is to have them sign a voluntary agreement to not compete for x amount of time.
Obviously, this can be abused in situations where employers have the upper hand. But in many high powered positions where highly qualified people have a lot of leverage against their employer, it could help reduce costs a lot (for the end consumer also, since the risk of someone leaving and taking the business would just raise the prices you have to charge to mitigate that risk, as opposed to a non compete).
In places like (e.g.) the financial sector, they have compensation for the duration of the non-compete. Many tech sector employers have no such concession. They basically want you to just 'not work' in the tech sector for the duration of the non-compete, which is completely not fair to the worker.
Yes, but consider this: you have a government-protected monopoly on your home when you own it. Imagine if anyone could compete for your home simply by occupying it. That would be economically ruinous.
Intellectual property is also a government-protected monopoly, created for the advancement of society.
Basically I'm saying that monopoly can be good or bad depending on the specifics. So competition can be very destructive in some cases.
Whether or not that should be legal is a different matter. Sometimes if all employers are doing it, it can result in an unfair and unhealthy environment for employees, however, sometimes if all employees can switch jobs willy nilly and take clients with them (especially those with strong relationships with clients), then it can become an unhealthy environment for employers.