The southern States that became the rebellion against the national government of this country, were defeated, after a long, bloody, and divisive war, in which, Constitutional amendments were passed, specifically the thirteenth through fifteenth amendments, that would once and for all, assert that all Americans, regardless of their color, creed, or former servitude were entitled to their full Constitutional rights. For a moment, perhaps, or at least as long as the north had a real military presence in the south, blacks, essentially for the first time in the deep south, were able to actually get elected to political positions and were accorded equal rights, but that lasted but for a blink of an eye in the skeins of time, and the defeated south, the defeated white men of the south, soon took back what was always theirs, total control of the political process, total control of policing and justice, and total control of what was permitted or tolerated within their communities.
The white man's animus against blacks, absolutely knew no bounds, for as plantation owners, the white man came from a perspective, that he had to be ruthless and efficient in carrying out "justice" against blacks, for the white man within his plantation, was sorely outnumbered, in addition to being obligated to protect and defend his children and in particular his invaluable and innocent white women. This meant, as a matter of course, that the white man, was always well armed, was always up on the latest local news, and always had additional men that could be called upon to aid him on short notice, in addition to the abiding fact that the justice system with its policing arm, knew what to do.
All of the above firmly put to the lie, that the black man was well treated, happy and complacent working as a slave, and that the southern way of plantation life, of taking care of these ill-educated and simple minded blacks, was akin to a Christian courtesy, that the north never seem to rightly understand, whereas the truth of it was always what it was, pure exploitation of another man's labor, so that the white man could live nice, free, and easy, off of enslaved people's blood, sweat, and copious tears.
The disappointment of black men living in the deep south after the civil war, was the immense disappointment of recognizing that this national government, seemed not to care, that their rights were abused on a constant basis, and thereby it wasn't until after World War II, that blacks in the deep south, began to make inroads on getting the most basic of civil rights, such as the integration of schools, the integration of neighborhoods, fair employment opportunities, fair representation in the judicial system, of which, all of this, they had to fight tooth and nail, inch by inch, because the obstinate southern ruling class, would not give up anything, not one thing, without a battle royal.
To sum up succinctly how much hatred, the white man had for the black man in the south, consider that these segregation laws, were specifically directed against blacks, so as to obviously keep those blacks in their place, so if you were an Asian man, of which, granted there were no many in the deep south, you could skate by and for the most part not have to worry about Jim Crow, for the laws and edifice built in the south, were specifically meant to separate and to subjugate, forever, the black man. So that those that today proclaim, how the laws have changed, and that everything is now on the up and up, that this therefore is an egalitarian society, are ignorant of the past, ignorant of the present, and ignorant of the future, for the black man has had to fight on the streets and through the justice system, to get what is theirs, and they still don't have it, cause the white man has never played fair, never will play fair, and doesn't have to play fair.