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.
Offensive vs Defensive. Think in terms of physical violence. Attacking someone else without legitimate provocation is offensive, ergo intolerant. Attacking someone who is attacking you is defensive, thus remains tolerant.
Pick any scenario and you can fit it into that construct with adequate context and nuance, there’s two sides to every coin, you just need to look close enough to see which side is up.