Throughout history, various races struggled from slavery, pretty much the entire spectrum is fully covered across the world. Nowadays there are more people in slavery than at any given time before.
It's not a coincidence that "Slav" and "Slave" sound so similar. And Slavic people are quite white indeed.
Exactly. Unfortunately for many Americans history stops in the last century and at the geographical borders of the USA.
Slavery in Russian empire was de jure abolished about the same time as slavery in US. Not surprisingly, it took even more time for "de facto" changes to happen with various restrictions still being a thing into 1970ies. If anything, kolhoz system was anything but slavery with the government being ultimate owner.