If humans are 70% water then Africans are only 30% human
Do you think that only applies to black people?
I'm going to tame them to be a human with whips!
What you have just said about humans being 70% water applies to all humans, including you and me, regardless of skin color, so it hardly justifies treating anyone as inferior.  Suggesting that you are going to attack people just makes yourself look violent, and this could lead to serious consequences if you keep it up.