Why did Sasuke's brother skunk kill the whole family in the first place?

He didn't kill him, but actually Uchibo Madara killed him. It turned out that he even killed Sasuke, but the skunk promised to take the fall for Diandian and join Xiao's organization. So I didn't kill Sasuke, so Uchibo Madara killed Uchibo.

Then why did you let Uchibo Shoko Asahara exterminate his own people?

In fact, Uchiha Shoko Asahara found that his family was planning to rule the ninja world.

You should know: if the Uchihiro family who owns sharingan really takes action, the consequences will be terrible.

So in order not to let more people get hurt, Uchihiro Shoko Asahara directly destroyed his clan and established the Xiao organization. The leader of Xiao's organization is Payne on the surface, but actually Uchibo Shoko Asahara (Teddy boy).

Authoritative information, absolutely correct. After typing so many words, it's god forbid not to give me points ~ ~ ~