This radical reconstruction of the South was deeply unpopular and slowly unravelled leading to the introduction of the Jim Crow laws.
The Reconstruction Era following the Civil War started to disassemble traditional aspects of Southern society.
Similarly, black men were known for having a specific lust for white women.
This created tension, as if white men were having sex with black women because they were more lustful, this meant black men would lust after white women in the same way, this threatened the white male dominance that was apparent at the time, increasing the fear of interracial interactions.
There was a rise in lynch mob violence where many black men were accused of rape.
This was not just senseless violence, but an attempt to preserve 'whiteness' and prevent racial blur, the whites wanted to remain dominant and make sure there was no interracial sexual activity.
Attitudes towards interracial relationships, and indeed marriage, have increased in positivity in the last 50 years.