Because white people generally ignore or are unaware of the real situation of African Americans.
Explanation:
When the author uses the expression "white world" he is referring to people with white skin. Moreover, when the author says that the white world is very ignorant and innocent, he is referring to the indifference white people have to the struggles and suffering that black people have been facing for centuries.
Answer: that means that snowball did something he was not supposed to do and did something opposite of his personality because he was different from a character.