Helping an old lady cross the street. Buying a friend a coffee and listening to their troubles. That is kindness: an ethical consideration for others, and a pleasant disposition.
It's absolutely essential to have design reviews be rational, and to untangle complicated emotions. The reason flight travel is so safe today is because of these principles -- crash reviews are not about assigning blame, but finding the cause of the crash to prevent further loss of life. But "kindness" does not come into play here, and introducing it will create problems, not solve them.
I agree with you, that the "bring the whole person" and "be yourself" part is unrelated good engineering practices. But these are the grounding framework of "psychological safety", which puts the responsibility for my well being in your hands. That's a responsibility that no one can (or should) bear.