It boils down to that is what the rich and those in power told them to. Before the Civil War African-americans were depicted as sub human. After the rich told poor people that the "lazy blacks were coming for the land and jobs." And that rhetoric still exists today.
Kreindor t1_ja6ekuo wrote
Reply to ELI5: Why did poor white’s in the South before and after the American Civil War have such a visceral hatred of African-Americans? by ScriptGenius12
It boils down to that is what the rich and those in power told them to. Before the Civil War African-americans were depicted as sub human. After the rich told poor people that the "lazy blacks were coming for the land and jobs." And that rhetoric still exists today.