Is speaking about some of the callers to bid'ah (religious innovation) and the Khawarij of this time by criticizing them considered backbiting about them?

Question:
He says: Honorable Shaykh, may Allah grant you success, many people speak about some of the callers to bid'ah and the Khawarij of this time by criticizing them and clarifying their errors. Is this considered backbiting about them?

Answer:
If they cause evil and fitnah (trial, discord or temptation), then it is necessary to expose their affair and reveal their disgrace so that people may be warned against them. If they transgress against people and cause evil to people, then it is necessary to expose their defects so that people may be warned against them.
As for if they do not cause evil, but only hold something in their hearts and believe it in their hearts, and they do not cause evil, then they are left alone and not targeted. The scholars say that one who holds the methodology of the Khawarij but does not do anything is left alone. But if he does something, then it is necessary to restrain his hand, it is necessary to fight him, it is necessary to stop him at his limit. Yes.