The real issue is not having laws to prevent firing someone for writing political incorrect stuff on social media not that mainstream media amplifies whatever someone posts on social media.
These laws could help though if it's just your boss who wants to fire you, but most of your colleagues would like to support you, even if silently.
Most (all?) of continental Europe actually has such laws, which is why you don't hear about american style firings here. So, your logic has been tested in practice and found out to be wrong.
This can give the victim some valuable paid time though.
Chances are the boss is just doing what's political correct too due the pressure put by various groups not what he/she badly wants.