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.
That’s true. But it also requires that both sides have the same definition of tolerance and the same definitions of good an evil.
It’s a similar problem to respect. If I said “I’ll show you respect if you show me respect” I could mean that I’ll give you due regard for your feelings if you’ll do the same. However, too often it means I’ll give due regard for your feelings if you’ll treat me with deep admiration.
