The teaching on these things (As stated in the Catechism of the Catholic Church):
2477 Respect for the reputation of persons forbids every attitude and word likely to cause them unjust injury. He becomes guilty
--- of rash judgment who, even tacitly, assumes as true, without sufficient foundation, the moral fault of a neighbor;
--- of detraction who, without objectively valid reason, discloses another's faults and failings to persons who did not know them;
--- of calumny who, by remarks contrary to the truth, harms the reputation of others and gives occasion for false judgments concerning them.
2478 To aviod rash judgment, everyone should be careful to interpret insofar as possible his neighbor's thoughts, words, and deeds in a favorable way:
Every good Christian ought to be more ready to give a favorable interpretation to another's statement than to condemn it. But if he cannot do so, let him ask how the other understands it. And if the latter understand it badly, let the former correct him with love. If that does not suffice, let the Christian try all suitable ways to bring the other to a correct interpretation so that he may be saved.
2479 Detraction and calumny destroy the reputation and honor of one's neighbor. Honor is the social witness given to human dignity, and everyone enjoys a natural right to the honor of his name and reputation and to respect. Thus, detraction and calumny offend against the virtues of justice and charity.
and the tradition, as demonstrated by St. Moses the Ethiopian:
A brother at Scetis committed a fault. A council was called to which Abba Moses was invited, but he refused to go to it. Then the priest sent someone to say to him, "Come, for everyone is waiting for you." So he got up and went. He took a leaking jug, filled it with water, and carried it with him. The others came out to meet him and said to him, "What is this, Father?" The old man said to them, "My sins run out behind me, and I do not see them, and today I am coming to judge the errors of another." When they heard that they said no more to the brother but forgave him.
[Abba Moses said,] "If the monk does not think in his heart that he isa sinner, God will not hear him." The brother said, "What does that mean, to think in his heart that he is a sinner?" Then the old man said, "When someone is occupied with his own faults, he does not see those of his neighbor."
and in the life of St. Isaac the Theban:
One day Abba Isaac went to a monastery. He saw a brother committing a sin and he condemned him. When he returned to the desert, an angel of the Lord came and stood in front of the door of his cell, and said, "I will not let you enter." But he persisted, saying, "What is the matter?" and the angel replied, "God has sent me to ask you where you want to throw the guilty brother whom you have condemned." Immediately he repented and said, "I have sinned, forgive me." Then the angel said, "Get up. God has forgiven you. But from now on, be careful not to judge someone before God has done so."
and St. Bessarion:
A brother who had sinned was turned out of the church by the priest; Abba Bessarion got up and went with him, saying, "I, too, am a sinner."
Let's not give the Accuser of our Brethren any jollies at all. We do not need to play his foul games and become ravenous mobs or bickering factions; each of us need only accuse no one but one's own self.