Ok, I had a couple of coffees and am choosing violence this morning.
Slavery was just a fact of economy for most of human history. Then Americans got a hold of it for a century and the world, pretty much collectively, said: that's fucked up, we should stop this.
America, faced with European armadas, decided not to import humans, but to make their own. Thus was born the rape based economy of the Southern slaves states. The plantations were actually able to increase the number of enslaved persons by no small margin.
As the Northern states. Industrialized and fostered a religious"middle class", this idea became more and more unpalatable. However, this was also eugenics and justification of slavery times. The church represented the progressive arm of politics at the time as it wasn't hindered by the economy. A brave few freed slaves had a lot to do with that as like was able to recognize like.
However there wasn't a mercy for African Americans that drove the general distaste of slavery, it was the economy of rape that made it so odious to Mr and Mrs Joe America who may or may not have had opportunities to interact with a segregated population, but generally could read.
Compromises eventually broke down via a fear of western states falling into slavery and the degredation of morals would destroy the country. This occurred in the backdrop of ethnic cleansing the native population. This was not a racially enlightened population, but a people, and economy, now motivated by family values.
Enter in the Civil war to put the kibosh on the progression of the institution of rape-slavery. Some of the enslaved populations were able to leverage uprising and the emancipation was sort of the only next logical step.
Reconstruction wasn't super successful and the slavery class was able to sink into the shadows, but still remain at the wheel. The culture of rape had already taken hold and was able to creep around immigration via racism and segregation became the new battle cry.
This is where a lot of prejudice against the South comes from. Think incest jokes, child bride, shotgun marriage, and wife beating general "family values" related criticism.
This economic power struggle leads right through prohibition and the enfranchising of women, marriage equality, feminism and is culminating in the anti-trans pedophilia fuelled fervor of the day.