What are the well-known controversial issues in which one must object due to the extreme weakness of the other opinion's arguments, or because it is objectionable or anomalous, and in which objection is not considered fanaticism or extremism? And are there any books that address this topic?

The matters of dispute that necessitate denunciation are those where the ijtihad (independent reasoning) is not considered valid by scholars, and which contradict a definitive, decisive text, whether the one contradicting is excused or not. No attention should be paid to the contradicting opinion, and it must be denounced because the issue is not one of ijtihad. It is difficult to enumerate all such issues. Scholars have clarified that the type of issues requiring denunciation are those that are definitive due to the clear establishment of a decisive text or a consensus. As for what is not so, there is no denunciation except through discussion and the presentation of evidence.

Therefore, the reprehensible act that must be denounced is that which is agreed upon by consensus, or that which contradicts a Sunnah or an ancient consensus. As for matters of ijtihad for which there is no apparent obligatory evidence that must be acted upon, one should not denounce those who act upon them, whether as a mujtahid (one who exercises ijtihad) or a muqallid (one who follows a madhhab).