Is the questioner's doctrine correct that it is obligatory to turn away from and abandon a disobedient person while they are committing a sin — whether major or minor — except in specific cases such as a Kitābī wife and polytheistic parents, where abandonment is obligatory only for major, expiatory, and trespassing minor sins, based on the premise that there is no explicit evidence in the noble verses and prophetic hadiths for not sitting in a gathering where a sin is being committed?

What you have claimed to be your doctrine—that attending gatherings of backbiting with disapproval in the heart is permissible—is a false statement, one that no scholar of the Ummah has preceded you in. You must know your place and not speak about the religion of Allah without knowledge. Backbiting is not a minor sin; rather, it is among the major sins. It is not permissible to abandon someone who commits minor sins while they are committing them, because minor sins are reprehensible acts. Attending gatherings of reprehensible acts, when one is able to leave them without objecting, is an affirmation of the reprehensible act. The listener is a partner of the backbiter. And whoever witnesses a sin and dislikes it is like one who was absent from it. If one witnesses it out of necessity or compulsion, then one should disapprove of it with their heart.