I suspect what the grandparent refers to is people who are offended at hearing "no." Example - someone asks to get in front of you at a line. If you're feeling kind, you say yes. Saying "no" is just neutral, but many people perceive it as a "fuck you."
No, it isn't. You can be unkind and peaceful. Civilization is based on the possibility that people who hate each other can still work together for the common good. Intentional kindness is often disgustingly hypocritical, at least in my (non-U.S.) culture.
