RE: What many revisionists and liberals fail to understand is that slavery existed on this continent long before white men set foot on it.
Yes.
See here:
https://en.wikipedia.org/wiki/Slavery_among_Native_Americans_in_the_United_States
FIRST PARAGRAPH:
Slavery among Native Americans in the United States includes slavery by Native Americans as well as slavery of Native Americans roughly within the present-day United States. Tribal territories and the slave trade ranged over present-day borders. Some Native American tribes held war captives as slaves prior to and during European colonization, some Native Americans were captured and sold by others into slavery to Europeans while others were captured by Europeans and sold into slavery, and a small number of tribes, in the late eighteenth and nineteenth centuries, adopted the practice of holding slaves as chattel property and held increasing numbers of African-American slaves.
Pre-contact forms of slavery were generally distinct from the form of chattel slavery developed by Europeans in North America during the colonial period.
Also, Native American Indians OWNED BLACK SLAVES!
SEE HERE:
https://en.wikipedia.org/wiki/Native_American_slave_ownership
Yup, and some in Mexico ripped their hearts out with obsidian knives while they were still beating.
They had elaborate public ceremonies where tens of thousands were murdered thusly on the same day, until the huge stone pyramids were literally covered in slippery blood.
Yup, it must have been good to be a Native American war slave.