Many slaves had a good relationship with their owners, and even took the family surname as their own on being freed.
It is politically expedient to not remind people that the wars in which large groups of people fought against others were fought over economic repression. From the Tea Tax and Stamp Act of the Revolutionary era to the tarrifs which effectively forced the South to trade with the North, economics are at the root of many conflicts.
Dig deeper, the truth awaits. The answers will make perfect sense if you understand why the colonies broke away from England.
While you dig, keep in mind that Uncle Tom's Cabin was a novel written by an ardent abolitionist.
Also, keep in mind that although many trimmings have changed, human nature is much the same. Hyperbole sold especially well in Northern markets, just as the wild-eyed stories of the "wild West" sold Harper's Magazine, and hype and gore sells Hollywood today. In reality, disease and suicide took far more soldier's lives in western forts than combat.
Truth becomes dispensible when there is a profit to be made, and the armies of victimhood swell their ranks with new recruits who are programmed with distortions and hyperbole, to the great benefit of their 'advocates'. The same tactics are used by just about any group which wishes to sieze power or wealth nefariously, from the Nazis to Islamists, to 'hate groups' of any ilk, regardless of race, creed, or nation of origin.
Good hunting!
Still does, and it is free!