Can you imagine what the world would be like to day if people where as afraid to speak their mind. How about the civil rights movement. Should they have kept their mouth shut because family and friends who hear and see them or those guys with the white hoods.
Fear is never a good reason to keep your mouth shut. If your employer is going to can you for being open then maybe you are working for the wrong people. If you are having to hide something from your family. It sounds like your family has issues. I can say anything to my family and I have no worry of doing so. They may not like it but what are they going to do disown me hate me... No my family isn't that way. Might I get an earful for something I say yep happens plenty of times.
But I refuse to live in fear no matter who the person is that is going to take issue with what I say. I didn't shut my mouth when I was in the Navy not when I worked for DOD/DLA not going to for anyone.