Condemnation is Self-Ridicule
Rabbi Moshe Ben-Chaim
“Anyone who condemns others is flawed, he will never praise others, and with his own flaw does he condemn” (Kiddushin 70b ).
Why is such a person flawed? Condemnation demonstrates that one’s energies are occupied with man, not God. He is competitive. Instead, one should be occupied with inner perfection, his relationship with God, and not with man. Preoccupation with others stems from ego and insecurity. Such a person lives a psychological life, where the social is a primary value. But Torah teaches that man is to be humble, which stems from disconcern for man, and to value wisdom. Torah dismisses social statuses and the need for human approval. Moses—the greatest man—was the most humble man. This was God's praise for him. The social is not man’s perfection. The perfected person care’s nothing for the approval of others, as he understands that reality exists to offer man the opportunity to uncover God’s wisdom. But imperfect man views reality as a platform to project his ego.
Another aspect of this social lifestyle is self esteem. Whether one assesses his specific trait or behavior as good or bad, is valued based on societal norms. Here again, one values public approval. And when one possesses a trait he deems negative, his ego protects himself and prevents self criticism, and instead, condemns another possessing that trait. He needs to vent his ridicule of the trait, but as he cant condemn himself, it is that specific trait he finds fault with in another person, although that other person may have 5 other flaws.