Shaykh Bin Baz said, “To boycott (a person of bidah) due to their innovation is obligatory; if they make their innovations apparent, then it is obligatory to boycott them after sincere advice and directing them.
A Muslim should advise his brother and warn him from that which Allah has made impermissible such as innovations and open sinning. This person will then either repent or he is deserving of being boycotted.
This (boycotting) is done in the hope that he will repent, feel remorseful and return back to the truth.
However, if the boycotting results in a bad outcome then it should be left alone.
If leaving off boycotting is more beneficial in terms of the religion, it is more good and closer to succeeding then a person should not boycott; rather one should be consistent in advising and warning from falsehood; one should not boycott him hoping that Allah will guide him due to this.
The believer is like a doctor, if he recognizes a cure that will be beneficial, he uses it; and if he realises that something will not benefit then he leaves it alone.
So boycotting is done as a form of rectification. If boycotting is effective and beneficial it is therefore from the means of rectification; hoping from the one who has been boycotted that he will repent and that he will return back from his mistakes if he sees from his brothers that they have boycotted him.
As for the situation where boycotting only leads to an increase in evil and an increase in the evil people…then in this situation a person should not boycott.
Rather a person should persist in advice, directing others towards good whilst showing a dislike for the action. A person should not show the person that he is in agreement with his falsehood however at the same time he persists in sincere advice and educating.” Ref: Madeenah.com
Posted by Abdul Kareem Ibn Ozzie