Backbiting Rulers is not Backbiting

The Messenger of Allah (sal Allahu alaihi wa sallam) said: “There is no sin in backbiting a person who has shaken off the screen of shame from his face.” [Ihya Ulum Id-Deen by Imam Ghazali]

To disclose the bad deeds of those who are accustomed to evil deeds openly is no sin; such as a male wearing female dress, a drunkard, a fornicator, or an oppressor.

Umar (radi Allahu anhu) said: “There is no honour for a great sinner (meaning those who commit major sins openly). He who commits sins secretly should have the honour of his fault being kept secret.” [Ihya Ulum Id-Deen by Imam Ghazali]

Hasan Basri (rahimahullah) said: “There is no fault in backbiting three persons; (1) one who is a slave of passion, (2) an open and well known transgressor, (3) a tyrant ruler. [Ihya Ulum Id-Deen by Imam Ghazali]