I don't think it has been established that he was fired. Even if he was, they didn't take away any of his free speech rights. He is still free to speak as much as he pleases, he just can't use MSNBC's equipment to do it.
Some have implied that since a clause in the contract exists to prevents him from going to another TV network for a specified amount of time, somehow this is restricting his rights. Again simply untrue. These clauses have a monetary amount attached to them, so he is being paid for that no compete clause. Also he signed the contract with that clause in it.
At their very core our rights a a guarantee of freedom from the government's interference. It is extremely hard for individuals (or companies) to infringe on a person's speech freedoms.
The general lack of understanding of our rights in this country disturbs me.
From the ashes.