And Shaikh Saalih al-Fawzaan was questioned about the same matter and here is the text:
Q. It has spread amongst the youth today amongst the youth that it is obligatory to counterbalance between to good and bad points/deeds when criticising and so they say: When you criticise such and such person for an innovation and you expose his mistakes, it is necessary for you to mention his good points/deeds – and this is from the perspective of justice and fairness. So is this manhaj (methodology) in criticising correct? And is it necessary for me to mention the good points/deeds when criticising?
When the one who is being criticised is from Ahl us-Sunnah wal-Jamaaah and his mistakes are in matters which do not relate to aqeedah, then yes… his good points/deeds and exceptional [qualities] are mentioned. His mistakes and slips are overwhelmed by his aid for the Sunnah.
But when the one being criticised is from the People of Misguidance and the People of Deviation and from the People of Destructive and Adulterated Principles, then it is not permissible for us to mention their good points/deeds – when he has good points/deeds – because when we mention them, this deceives the people and makes them hold a good opinion about this strayer or about this innovator or deviant or parisan (one engrossed with party-spirit). So then they accept the ideas of this strayer or this innovator or this biased partisan. And Allaah jalla wa alaa refuted the Disbelievers, the Criminals and the Hypocrites and did not mention any of their good points/deeds. And likewise the Scholars of the Salaf refute the Jahmiyyah and Mutazilah and the People of Misguidance and they never mention any of their good points/deeds. This is because their good deeds/points are impaired by their misguidance, disbelief, deviation and hypocrisy. So it is not befitting that you refute a straying wanderer, innovator, deviant and then mention his good points/deeds and that you say he is a good man, he has this and that good deed/point, but he made a mistake! We say to you: Your praise of him is stronger than your his misguidance, because the people will hold on to you praise of him. So when you promote this straying innovator and you praise him then you have deceived the people and this opens up the door for accepting the ideas of those who lead others astray.