Legally yes functionally no. If you doubt me start expressing your political opinions publicly and see how long you keep your job. You have freedom of speech, you don't have a right to employment. Unless you are too rich to care you don't have free speech.

It's perfectly legal for me to fire you for your political opinions in most states. I can't fire you for being gay, I can't fire you for being a member of a church. But if you say I'm voting red or blue, I can fire you.

Political identity is not a protected class in the US, I can just as soon fire you for being a Nazi as I can for you voting for Biden. I can go into the parking lot and use the bumper stickers on the employees cars as a basis for layoffs if I want.

Freedom of speech? Freedom after speech? It's all a kind of public religious creed. A high political ideal that like most things is far abstracted beyond it's functional being. Americans get teary eyed and their voices quake when partaking in the public liturgy of our founding fathers freeeeedom and the like, they get angry and yell during the two minutes hate. What does it all mean in the end? What freedoms do you enjoy? Does the freedom to own a gun mean anything when the government can simply remove that freedom for any number of reasons, like saying you want to use it? Does it mean anything if someone else can simply shoot you to take it.

Perhaps so, as the only true freedom is death.