Some of the Sunni exegete believes:
The revelation of the verse was related to the protection of the Prophet (PBUH) in Medina not in Ghadir.
Some Sunni Muslims resort to some traditions and say that until the revelation of the Verse of Proclamation the Prophet (PBUH) was protected by guards but after the revelation of this verse and God’s guarantee on the protection of his life, he dismissed the guards and said the Almighty God would protect him. Therefore, this verse, revealed elsewhere, is basically on the protection of the Prophet (PBUH).
And Shia response to this confusion is:
First, the claimed traditions, in case of authenticity, do not intend to explain the reason for the revelation of the verse, to negate any use of the verse. Rather, it is about the closing sentence not about the major and most important meaning of the verse. On the other hand, some traditions assert that the dismissal was made by the Prophet (PBUH) in Medina, and it was not a commandment by God to be announced in Medina and within his last hours before demise.
Second, Sunni Exegetes basically say that those traditions are strange. They are unanimously of the opinion that since the Verse of Proclamation was sent in Medina in the final days of the Prophet’s mission, it has nothing to do with protection of Abu Talib in Mecca.
Third, the argument of some Sunni exegetes who resort to the protection of the Prophet (PBUH) and say it was once revealed in early years of prophetic mission when Abu Talib was responsible for protection of the Prophet (PBUH), and another time, in the final days of the prophetic mission when special guards protected him, is basically baseless. This is because the evidence in this verse on leadership of Imam Ali (A.S) is found in the beginning of the verse.
Translated by: Sadroddin Musawi
 Tafsir ibn Kathir, Vol. 2, P. 79