> Private entities such as your employer can restrict your speech in many ways.

Fun fact: Europe actually has better protections for free speech for employees. Even if you're a hardcore Nazi taking part in actual Nazi rallies, unless you're wearing company clothing or are a high-ranking corporate official, you can't get fired for that. And when you, say, contribute to an open source project in your non-work time on your own computer, your employer doesn't get any rights to that code.