Maybe it's not about cars as much as about battery technology for which Tesla is known. That's a major concern for Apple.
It's the car. Just few days ago it was reported by WSJ that Apple's Project Titan was made a 'committed project' which means it's being targeted for release.
Isn't the anti-compete for stuff like this? And they won't be able to work on tesla-technology-related projects
Non competes for employees are generally void and not enforceable in California. [1]