It is haraam to injure others and to call each other by bad names. He dislikes calling others by words or names that offend him. Because he was insulted and ridiculed and wounded. His heart was hurt. But no man should hurt his brother in this way. This makes people's mood worse. The boundaries of brotherhood are violated. This work is against general courtesy and taste.
Islam wants the people of the Muslim society to live with a clean, pure and innocent mind towards each other. May absolute trust and dependence on each other be stable. Let there be no doubt, distrust and mistrust towards each other. No one should have a bad opinion of anyone, no one should make false accusations. This is why in the aforesaid verse this word has been mentioned as the fourth forbidden act. Because Islam is not ready to tolerate the degradation of human dignity under any circumstances. Because some ideas are sinful.
Needless to say, the idea here is to have a bad idea, so no Muslim should have a bad idea about his Muslim brother, as long as there is no conclusive evidence.
People have to take it for granted that they are innocent. Whispering bad ideas will convict innocent people, it should not be. The Prophet (peace and blessings of Allaah be upon him) therefore said stay away from bad ideas about people. Because misconceptions are very false.
It is true that human beings are not able to keep themselves away from misconceptions due to human weakness. Doubts arose in their minds about some people. Especially about those with whom the relationship has deteriorated. But it is the duty of a Muslim not to succumb to that evil notion, that is, not to give him space and not to run after him. At this stage also the hadith has been narrated. If you have a bad idea in your mind, do not consider it to be true.