Shaykh Saalih Bin Abdil-Azeez Aal Ash-Shaykh said, “Tying Muwaazanaat* to justice is inaccurate. Because the principle of muwaazanaat is sometimes truth and sometimes rejected, so implementing muwaazanaat in some matters (is correct) and rejected in other matters.
Therefore, whoever looks at the way of Shaykh Al-Islam (Ibn Taymiyyah) will see that he mentioned the good and bad in some matters that are known, and in his judgement on some groups even on some Mu’tazilah and Ashaa’irah (two misguided sects). And (in contrast) he did not implement this principle (muwaazanaat) in some matters.
Muwaazanaat is not implemented in the context of rebutting an opposer or an innovator or a misguided person. Because if you mentioned the good of this rebutted (person) or innovator or misguided person or oppressor you (would be) seducing (the laymen).
In contrast, Muwaazanaat (the good and bad) is mentioned if the intent is evaluating a person, an author, a book or a group etc.
As for taking this principle generally and ascribing it to the Salaf, it is inaccurate.”
Ref: transcript audio (the principles of laying principles), pages 18-19
* (My Words) al-Muwaazanah is an innovated principle which is not from the manhaj of Ahlus Sunnah (methodology) in criticising Ahlu Bidah (the people of innovation).
Muwaazanah involves counterbalancing between the good and bad points of a person when criticising that person.
So when a person is criticised for a error or innovation this principel makes it is necessary/obligatory upon the criticser to mention the refuted persons good points and bad points. This is claimed to be done from the perspective of justice and fairness.