A restriction of your freedoms, whether protected or not, is a restriction of your liberties.
Some liberties are constitutionally protected. Some are protected by state law. Some aren't protected at all. They're all still liberties though.
Similarly, an employer restricting topics of conversation in the workplace is in fact placing restrictions on your free speech. It's just not constitutionally protected in that instance, is generally permitted by state and local law, and seems to be largely culturally acceptable.
A restriction of your freedoms, whether protected or not, is a restriction of your liberties.
Some liberties are constitutionally protected. Some are protected by state law. Some aren't protected at all. They're all still liberties though.
Similarly, an employer restricting topics of conversation in the workplace is in fact placing restrictions on your free speech. It's just not constitutionally protected in that instance, is generally permitted by state and local law, and seems to be largely culturally acceptable.