Wiki - The paradox of tolerance states that if a society is tolerant without limit, its ability to be tolerant is eventually ceased or destroyed by the intolerant. Karl Popper described it as the seemingly self-contradictory idea that in order to maintain a tolerant society, the society must retain the right to be intolerant of intolerance.
An Italian left-wing comic author once said that neo-fascism has been normalized so much that Nazi is the only term left, but perhaps that applies only to his country.