Isn’t the connecting element between your piece and Keri’s that a person’s character is not static, and their actions are obviously varied?
Obviously if a stranger is coming through the window of the house with a knife, we’re not inclined to philosophize about there being no ‘good’ or ‘bad’ people while that person brandishes the weapon in our face — but even they have some background story to becoming who they are.
Just taking myself as the example I know best, my past is littered with actions where I know I did something decent for humanity as a whole, and others where I could still cringe to realize that it was actually me who behaved with a monumental level of stupidity.
Sure — judging people is pretty basic to navigating the world, but I’m suggesting that you do not need to ‘damn’ those who you choose to steer clear of. I think Keri was maybe getting more at the badmouthing aspect of some people’s mental behavior which can reach a point of systematically refusing to see any redeeming features whatsoever in those one needs to believe are ‘bad’ in order that one can believe oneself to be the opposite.