At least in the United States it would probably be challenged a violation of the Constitution, though corporations also have immense power and influence, and sadly most people would probably just go along with it for fear of losing their job.
Discussion
I see it as a total violation of our constitution , but it’s been trampled on since I was born in 73, unfortunately it keeps getting worse. I googled “can a company be sued by an employee for making them post the on social media”, the only results I kept getting were employees getting sued and held liable for what they say on social media ,, nothing about the employee rights go figure