you specifically proposed that people must explain that when they word 'scam' or 'scammer' they must explain how this was true of Rossi for the past six years. I am asserting that your proposal is absurd. As evidence,
Sigmoidal in the Universal Declaration of Human Rights (art 11) "Everyone charged with a penal offence has the right to be presumed innocent until proved guilty according to law in a public trial at which he has had all the guarantees necessary for his defence." see e.g. https://en.wikipedia.org/wiki/Presumption_of_innocence
So anyone accusing Rossi to be a scammer should be able to prove that in Court.
Writing that Rossi is a scammer "by evidence" or with generic or ill based statements have no sense.