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.
It is, indeed, a broad question.
Is it “physical violence” when a Nazi shoots a Jew?
Is it “physical violence” when a Jew shoots a Nazi?
What if the Jew in question were David Berkowitz, and the Nazi in question were Oskar Schindler?
Depends on the context.
Why is either shooting the other?