By inquiring about the plot information of the short video "Xiao Mo of Zhuang Nationality", we know that the reason why Uncle San left is not the contradiction with Xiao Mo, but mainly to pursue a new life, change a living method and enjoy the fun and comfort of life with his masked brother.

The fundamental reason for his leaving is the problem of money. If he can earn a lot of money in Xiao Mo, I believe his uncle won't leave. He also thinks that being with masked brother can make a lot of money and improve his life.