Wrongful termination of employment over a Freedom of Speech Issue?
Is there some such provision in Phil Robertson's employment contract?
If not, then what book of collectivist dogma does that ridiculous notion come from?
There's no such thing as "wrongful termination of employment" unless such termination is in breach of a contract which was signed by both parties.
In the absence of such an employment contract, the ownership of a company has an essentially absolute right to terminate any employee for any reason, or for no reason. There is not some unalienable right to keeping a job when an employee is no longer wanted by a company's ownership.
That's only partially true. If such termination occured due to race, religious beliefs, sex or age, that's called discrimination and there ARE employment laws against it.......
In fact, your employer likely has a government mandated Equal Opportunity Is The Law" poster in plain view for all employees to read and it might even look like this: