There is nothing special in US slavery, except it happened in US and US has been culturally relevant for the west since the end of WW2
One thing is the historical reasoning about it, another is thinking that it happened only to one place in the world and only those people can talk about it.
Don't get me wrong, slavery is a terrible and unjustifiable crime, but it didn't start in US and it didn't end in 1861
The United States was not the only country to ever employ chattel slavery - it's not unique in that regard. It is unique in that it's the only country to end slavery due to civil war - a fact I think is very important in this discussion. There are to this day a number of "rebels" as they call themselves who believe themselves to be intellectually and morally superior to black people, they want to keep black and whites separated, and they want to remind blacks of their inferiority by prominently displaying statues of Confederate Generals in the public square and promulgating the use of terms reminding blacks of their inferior social standing. Terms such as blackmail, blacklist, and master/slave. There's way more behind this than just slavery and snowflakes getting their feelings hurt.
Isn't it weird that people that don't know words etymology want to decide what they mean for the rest of us?
> 1550s, "tribute paid to men allied with criminals as protection against pillage, etc.," from black (adj.) + Middle English male "rent, tribute," from Old English mal "lawsuit, terms, bargaining, agreement," from Old Norse mal "speech, agreement;" related to Old English mæðel "meeting, council," mæl "speech," Gothic maþl "meeting place," from Proto-Germanic mathla-, from PIE mod- "to meet, assemble" (see meet (v.)).
In 1550 USA didn't even exist, not even in the form of colonies, that formed after 1600.
The first known settlement in what we call US today is by the Spanish in 1513 that reached Florida.
So no, blackmail doesn't mean what you think it means and doesn't come from where you think it does.
In UK for example anti slavery movements are born during the civil war as well.
But chattel slavery was already abolished for a period in the 12th century, before the Norman occupation that reinstated it.
US abolished it after a civil war because every other country already did it without having to kill each other, but civil war was really about money and taxation.