But as part owner of the company through stock, the former employee is free to disclose whatever they like, unless specifically contracted to do otherwise, aren't they?

Don't want all your private company secrets legally broadcast to the public? Be careful who you grant shares of ownership to. Can't trust your employees? Guess you have to find something besides ownership to incentivize them with.

The quoted law doesn't look to make any special provision for that. I'm not sure if that's an oversight or intentional.

Does the word "equity" mean anything anymore?