The Ruling on Backbiting One Who Displays Religious Innovation or Open Sinfulness

Question:
Does speaking about the innovations of other sects and religious schools, such as speaking about the innovations of the Sufis or the Shi'ah in gatherings or among the Rafidah, does this speaking fall under the ruling of the forbidden backbiting?

Answer:
Speaking to denounce innovations and to denounce open evil is not backbiting, but rather it is advice and the forbidding of what is wrong, as mentioned previously regarding the exceptions in fasting. One who complains, is known, and warns people about innovations and open evils is not committing backbiting, but rather it falls under the category of forbidding what is wrong and warning against evil.
The books of the people of the Sunnah are filled with refutations of the people of falsehood by their names. We understand their writings where they refuted the people of innovation, named many of them, and warned against them. Among this is what is established in the authentic collections.
That the Prophet (peace and blessings be upon him) , because they mentioned open evil. They mentioned open evil. They said so-and-so, as mentioned regarding funerals, they said so-and-so does such and such and such and such of the open matters and open wrongs. So the Prophet (peace and blessings be upon him) did not consider this backbiting, and he did not rebuke them because they mentioned something open that was concealed.
Among this is that a man from the worst of people, who was known, asked permission to enter, and he said, "Let him in; what a bad one of the tribe," or he said, "What a bad son of the tribe." Yes.