Because he doesn't like it there.
>nor what it announces it on Twitter before getting a new job.
Because it's his Twitter and he has nothing much to hide. It's not like he wont find employment (actually it might be not like he even needs employment that badly -- he could easily have a couple of million in the bank).
More likely the other way round.
Impetuous quitting over some specific issue he holds dear is only a thousand times more likely.
acting or done quickly and without thought or care. "her friend was headstrong and impetuous" synonyms: impulsive, rash, hasty, overhasty, reckless, heedless, careless, foolhardy, bullheaded, headstrong, incautious, imprudent, injudicious, ill-considered, unthought-out
If you reread my comment, it didn't say he didn't have a good reason, just that he might have acted quickly or emotionally. Like many of us do.
It's not necessarily rash, foolhardy or reckless, since those are synonyms. In this case they are similar, but not exactly the same.
"Chris just wasn’t the right fit for Tesla, and we’ve decided to make a change."
Still strange that a guy so super successful inside and out of Apple couldn't fit there. My guess is he was a bad fit for the role, Tesla said how bout we move you to another role that fits you better, and Chris said "no".