How can one respond to the argument that Ali (as) is not infallible based on his refusal to erase what the Prophet (s) had told him to do during the treaty of Hudaibiyya?
When the Prophet of Islam (SAWA) had the Treaty or the Trues with Mushriks of Makkah, they did not accept the writing of Hazrat Ali a.s who wrote that this is a Trues between Mohammad the Messenger of Allah and the people of Quraish. They said : If we accept you as a Prophet we would have never fought against you. So they wanted Ali a.s to omit the word Rasool Allah. Ali as did not accept and did not obey the Mushriks and said : I will never remove it . then the Prophet of Islam himself for the sake of safety of Muslim removed it. There is no question of the Prophet (sawa) ordering Ali a.s to do something and Ali a.s disobeying him because the Prophet (sawa) has clearly said in authentic hadiths that Ali a.s is with the truth and truth is with Ali a.s, and said also: Ali a.s is with the Quran and Quran is with Ali a.s. So, no possibility at all that Ali ibn Abi Talib a.s does anything away from th obedience of Allah and the Prophet sawa. The enemies of Ali a.s wanted to create doubt about this Incidence of Hudaibiyya but they are trying to play mischief and not going through the real authentic narration about what happened in Hudabiyya Ali a.s never disobeyed the Prophet saws but he kept the respect of the Prophet sawa being the greatest and the final Prophet sawa of Allah and he did not omitted the word of the messenger of Allah, then the Prophet sawa omitted it himself for the safety of the Muslim Ummah. that is what happen in Hudaibiyyah.
Wassalam