Is it obligatory to attend gatherings of relatives where there is excessive idle talk, backbiting, and forbidden acts, despite this contradicting the Quran's commands to avoid idle talk, and despite it displeasing one's parents?

Obedience to parents is obligatory, except in disobedience [to God]. Attending family gatherings that parents command is obligatory because it involves maintaining ties of kinship, while denouncing evil gracefully. If they do not respond, one should then distance themselves, apologizing politely, for Allah the Almighty says: "And when you see those who engage in [offensive] discourse concerning Our verses, then turn away from them until they enter into another conversation." The important thing is to combine maintaining ties of kinship and pleasing parents with avoiding falling into the forbidden.