What would/should actually happen in this case is HR/the manager would meet with the employee and ask them to vent any apparent frustrations. If the statement w

What would/should actually happen in this case is HR/the manager would meet with the employee and ask them to vent any apparent frustrations. If the statement was made publicly, they would probably be fired outright for making public statements about the employer without permission. If it's only internal, they wouldn't be fired outright, but they will likely be passed over for promotion. Makes sense, why should a company invest in someone who apparently isn't invested in the company? If they are ever fired, the reason given would be for some other unrelated infraction that they are legally allowed to terminate for.