Slavery in our historical presentations has become somewhat a national distraction tactic.........in world history its often a footnote, it used to be in US history......because often, in reality it is/was a footnote to a primary subject...It's an uncomfortable subject. Many folks are incapable of discussing the subject without getting emotionally invested, or charged. Like plenty of other subjects, this brings out the virtue signals, & personal attacks. Lots of folks don't want to have an honest discussion, & plenty of other folks, don't want to subject themselves to such attacks.
It's a discussion tactic that has shown to be very successful. The way to dispel, or discredit an uncomfortable truth, is to claim the higher moral ground. Most of the time, this allows the messenger to be discredited for being immoral ie: racist/white supremacist. Regardless of whether or not, their position/statement is historically accurate.
Sadly, many folks don't want to hear the truth. Instead, they prefer what makes them feel good, or what helps them to achieve their personal, or political goals. Follow enough of these discussions, & you'll see plenty of evidence to back up my assertions.