The truth about slavery is that it was legal in this COUNTRY (the US) for 80 years (1783-1863), and in four years we’ll reach the point WHERE IT HAS BEEN OUTLAWED FOR TWICE AS LONG (160 years) - 1863-2023.
The “400 years” BS is just stewing race-hatred; chase down Britain, France, Spain, and Holland for that.
I don’t separate the English colonies from the United States that way. My ancestors were Americans in 17th century Virginia and Massachusetts. Some of them owned slaves. While I don’t feel guilt, I’m not going to say it doesn’t count and blame the Brits. It was us, a continuing political and social enterprise.
You need to read some history if you think the Emancipation Proclamation ended slavery in the USA. English, Irish, Italian and Chinese slavery in the USA continued well into the 20th century. My grandmother came to the USA from England in 1913 and worked as an indentured servant for six years to repay her sponsor, all with my toddler father in tow. I knew her and heard the stories first hand. I also heard the stories of my Irish sharecropper relatives whose lives were destroyed by Sherman despite the fact that they never owned slaves and never supported slavery. Unless you include these groups you simply cannot tell the “truth” about slavery in the USA.
Using the left’s own language against them, slavery was a legacy of the empires that occupied what was to become the United States. There was unease and controversy about slavery from the country’s founding - many saw it as incompatible with our founding principles, but others said the states had the right to continue slavery. The United States eventually got rid of slavery. Capitalism helped to overthrow slavery. Karl Marx noted that the capitalist/industrial North fought against the system of the feudalistic South (something today’s leftists ignore).
Don’t forget Portugal.