Apple doesn't own people. If employees want to change employer, they are free to do so. Apple of course knows this, so it tries to terrorize current and future employees into submission.
I worked at an SaaS offering for market research surveys that was threatened with a lawsuit because we hired a software engineer who used to work phones in a call center that specialized in polling people. He signed the non-compete contract, obviously, but the point was to discourage him and other people from quitting, or their potential employers from hiring them.
The idea is to make illegal lawsuits against people who broke no laws, so as to set an example for other people who are thinking about quiting.