There are similar protections in Europe. I can understand firing somebody if they are a public face of the company. For example, if your name is on the product, you speak publicly for the company, or if you link yourself to the company on the platform in question (e.g. mentioning your employer in your bio). Just a random person in a company should not be fired, even if they get doxed, this revealing their connection.

It can get more complex. That example working for the ADL while having Nazi appreciation as a hobby would be a problem. There are things we might do outside of work that makes a job untenable.