Outside of California, they do.

Except James Damore wasn’t one but got labeled so anyway. It’s not okay to selectively allow or prohibit speech. Everyone should be able to say anything. It’s just words.

You can say anything you like.

What you're actually asking for is that people can say anything they like without repercussions of any kind.

That's a different thing. ...and, legally, it's been a thing (see 'libel laws') that freedom of speech does not guarantee for a long time.

/shrug

So you cannot say anything you like.

Or by that reasoning you could say anything you liked in the Soviet Union when Stalin was the big cheese but of course there were repercussions. Once upon a time we were taught there was a /fundamental/ difference between freedom, justice and Stalin's Soviet reigime that we were (and still are) dead against. The difference, which is a significant one right now, is not fundamental. It is just a difference of degree of those repercussions.

Interesting isn't it?

He used company resources and an internal forum so that doesn't fit under OP's description of being "a private citizen representing the opinions of yourself."

And he was fired for creating a hostile work environment for his colleagues. Not for his private views.