Seriously, no one who knows history at all can fail to know both that racism and slavery were universals the world over, UNTIL US.
Asia, Africa, North and South America, Europe. Maybe the Australian aborigines didn’t practice it, but the Maori in New Zealand definitely enslaved one another.
One of the main products of Viking raids was white slaves.
Here is the thing: for most of human history, if someone was not a direct member of your in-group, they had no rights and no claims on your conscience. This is a fact, an historical fact.
The racism of the present Left, the hatred, the depersonalization, the demonization, the violence: all very, very old, atavistic, and actively regressive. We should have grown past all this a long time ago. We really should have.
Part of the problem is that we have given our world over to people who deal well with abstraction, and far too many of those people are emotional grotesques. They are ugly on the inside, in ways not hinted at even remotely by how awkward and/or banal they are on the outside.