From Real Life Villains Wiki
"Go back to Africa" is a common negrophobic slogan for white supremacists, especially during the Civil Rights Movement.
I hate niggers.
~ Dylan Klebold

Negrophobia is a dislike, hatred or fear of Black people, cultures, countries and etc. It can range from general dislike to police brutality, violent hate crimes, even murder (most commonly lynching.) It can also include stereotypes, such as that all Black people in a country such as the US are undocumented immigrants or criminals. Negrophobia is strongly associated with the White Power Movement and was most prevalent during the post-Civil War slavery and Jim Crow eras in the United States.