Earlier quoted context omitted.
What would being unkind accomplish here?
It's not about being unkind, it's about not being kind; these are not the same. Being kind to a person that behaves as described in the grandparent comment could communicate that you find this kind of behavior helpful. Fine if that's really the case; problematic for everyone if not.
I think most people would agree Fred Rogers was kind - but I have to imagine he had to fire people from the show over the course of its run.