Challenge to Sunni and Shia folks !

This hadees is directly from sunni's most authentic book. It is totally irrelevant here whether this sahabi narrated ghadeer or not. However, I wonder what are the things he was regretting about?

BTW shia got their knowledge of Ghadeer directly from the Imams not from a second hand source.

This is the difference between the two, you have hadees that start like "so and so heard it from so and so.....", while shia get the hadees directly from Imams.