The opening passage of the 7th Chapter of the Zhuangzi contrasts two ruling styles and, by inference, two radically different ways for us to relate to the world. It begins with a disciple who is "ecstatic" at hearing a sage three times declare that he does not know. His teacher amplifies the implications of this not-knowing: One style of ruler, because he "knows", embraces Humanity and imposes it upon others so that "he never gets beyond criticizing people, considering them wrong." (Ziporyn)
There is a brute and powerful simplicity in this declaration that criticizing people demonstrates a lack of sagacity. That we all do it makes it all the more a powerful opportunity to explore the nature of our relationship with the world. If self-inquiry is an exercise we value, then we could do no better than to examine why it is that judging others is so much a part of who we are. Why do we do it? What would it feel like to not do so? What kind of awareness would it be that was free of the need to criticize others?
"Humanity" is a cardinal Confucian value and might, for the sake of simplicity, be defined as "kindness". How could kindness lead us to an unkindly judging of others? We "know". We know right and wrong, should and should not — we know how others should be. And because we know, we apply what we know. But to apply is to impose. True kindness is not kindness applied, but kindness spontaneously arising. This is wu-wei.
The alternative style of ruler is introduced with the surprising declaration that "sometimes he thinks he's a horse, sometimes he thinks he's an ox." This is, I believe, a metaphorical way of saying he has no-fixed-identity. Freed from a static and fixed sense of self, not-knowing (or caring) precisely who even he himself is, what "knowing" does he have to impose on others? Or, if one moment he can be a horse and another moment an ox, how can he not also be the others he would criticize? Unfixed, who is there to judge or be judged?
There are other dynamics involved, of course. Self requires others. Others, to be others, need to be different. Criticizing them makes them so. The problem with self is that it knows itself to be an empty delusion and therefore must forever attempt to make itself real by not being someone else. "Not that" makes our "this".
This may or may not have helped to clarify the reason we criticize others, but the important thing is that we understand that, within the Daoist sensibility, it is this inclination to criticize which provides us with a wonderful opportunity for self-inquiry should we wish to do that work.
You can check out Scott's writings on Zhuangzi here.