Also I should add.... Jordan is not being silent... He spoke out on medium where the power relationship is more balanced and in a venue where his voice will be heard.
He is warning others to make a different choice and to stay away.
Sending a parting shot to someone who doesn't care is not breaking the silence. The boss just deletes the email and points to it as proof that Jordan was a bad fit, such an email is a waste of energy and a weapon to be used against the sender
I would have not bothered to send the email that is my only feedback.