Justified to me. I spent some time reading on that Federal Law concerning the situation, it's more about protecting worker unions, being able to state their demands etc. There is discussing and criticizing, and then there is insulting (plus since I haven't seen the exact post, it's not really clear whether she was trying to organize people, to state some demand or criticize. The law doesn't seem to be about venting). I sure hope there isn't a law that forces an employer to keep an employee who writes vulgarities about them/the company (as mentioned in the article, I have no idea what they are, except for the quoted remark.)
I don't see Facebook as something that should be treated differently. Would a boss have to keep that employee if instead of publishing it on Facebook she had told the same thing in person, to several people? Or sent emails to them?
edit: However, that is based on her specific behaviour, not in regard to any employee who writes whatever, in a civil manner, about their company on a website. As such, I do not agree with the company's policy: violating a policy that bars employees from depicting the company “in any way” on Facebook or other social media sites in which they post pictures of themselves.
