Freedom of speech is a right of the people against the government. Not between employees and employers. The level of frank discourse a corporation will tolerate

Freedom of speech is a right of the people against the government. Not between employees and employers. The level of frank discourse a corporation will tolerate is based on its individual culture and subject to change. This is an oversimplification as there may be other labor laws at play based on the circumstances, but as far as a Constitutional right to free speech, it does not extend to the workplace.