Green light for insulting and slandering from al-Khui

Salam alaikum.

This fatwa from Grand Aytollat Abul Qasem al-Khui.

السؤال : وهل يجوز سب أهل البدع والريب ، ومباهتتهم والوقيعة فيهم ؟
الجواب : إذا ترتب ردع منكر على تلك ، فلا بأس

“Q: Is it permitted to insult the people of Innovations and Doubts, as well as slander and abuse them?
A: If that results in pushing back of Evil, then there is no problem in it”.

No wonder why are they so quick on insult.