Are you serious?
I don't know about Italy, but in some countries defamation is cause/grounds for prosecution.
Let me give you an example. In Thailand, if you air your grievances on social media and defame a company online, they can actually sue you.
For example, if I say that Food Panda are unreliable shitcunts, or Lazada are thieves, my statements can be considered defamatory, and the aforementioned companies would have just cause if they decide to seek recourse.