Is it permissible to revile and curse Al-Hajjaj, taking into consideration his Islamic conquests, and is he considered to be from the transgressing party (Al-Fئة Al-Baghiyah)?

One should refrain from cursing Al-Hajjaj ibn Yusuf, because a specific transgressor should not be cursed individually, either prohibitively (haram) or out of caution (tanzih). However, if oppressors like Al-Hajjaj are mentioned, one may say: "Verily, the curse of Allah be upon the oppressors." There is no objection to mentioning Al-Hajjaj's flaws, injustices, and wickedness. Indeed, Al-Dhahabi described him as an oppressive, tyrannical shedder of blood, and it is obligatory to hate him for the sake of Allah. His sins overshadowed his good deeds, and his affair is with Allah.