He spoke about boycotting the open sinner.

The Shaykh : This topic is related to the principle of boycotting known in Islam, or boycotting for the sake of Allah. We often ask about a companion or friend who does not pray, smokes, or does such and such. Should we boycott him? I tell him, do not boycott him, because your boycotting him is not beneficial to him. On the contrary, it pleases him and leaves him in his misguidance. I recall, on this occasion, a story about a man from the Levant regarding that open sinner who had abandoned prayer. He repented and went to pray, or to pray in the mosque, and he found the door locked. He said to him, "You are a drunkard, and I am one who does not do that." So this open sinner, whom this righteous Muslim wanted to boycott, was not in a state of [repentance]. He said, "You are a drunkard, and I am one who does not do that. I do not want companionship, because the companionship of the righteous with the wicked restrains him from his wickedness. And this wicked person does not want that. So if the righteous person boycotts him, that is what he wants. Therefore, boycotting is a legitimate means intended to achieve a legitimate benefit, which is disciplining the one who is boycotted. If the boycotting does not discipline him, but rather increases his misguidance, then boycotting is not called for. Therefore, we should not cling today to the means that the Salaf used, because they acted from a position of strength and security.