Is saying "perverts" or "the epitome of perversion" to oneself about people who commit abominations considered backbiting, and must one seek their forgiveness for this statement?

Whispers of the self (hadith al-nafs) are not considered backbiting (gheeba), for backbiting is when a Muslim mentions his brother with what he dislikes. If you utter a word like "transgressors" (fussaq) or similar, intending individuals who openly commit sin, then there is no sin upon you; because the one who openly commits sin, it is not forbidden to backbite him concerning what he is open about.