Was Ali (may Allah be pleased with him) the killer of the most wretched of this Ummah, even more wretched than the disbelievers and hypocrites, or does the hadith have another meaning?

The prophetic narration: "The most wretched of people are two: a red-faced man who Hamstrung Salih's she-camel, and the one who stabs Ali," has many authentic chains of transmission and has been authenticated by Al-Albani. Scholars differed concerning the disbelief (kufr) of Ibn Muljam. Those who affirmed his disbelief cited this Hadith as proof, while those who maintained he did not disbelieve, because he was an interpreter (muta'awwil), held that the Hadith must be interpreted to mean that Ibn Muljam was the most wretched among the people of the Qibla, just as the one who Hamstrung the she-camel was the most wretched among the people of disbelief. The preponderant opinion is that he committed an act of disbelief (kufr), which is consistent with the apparent meaning of the Hadith.