That origin story about Black Friday is actually a myth, perpetuated by retailers to supplant the real original of the day, which has a decidedly more negative connotation, same big insurance companies and same banks since slaves trade period in USA.
But well known Black Friday story (covered or lets forget brutal of the past), started in 1960s by local incidents in Philadelphia.
Either way, the city itself even attempted to change the name of the day to "Big Friday" to remove the negative connotation, but it didn't stick. It wasn't until fairly recently, in the late 1980s, that the term spread around USA as a result of retailers spinning the formerly negative concept into the bargain-shopping bonanza it has now become.
CAPITALIST - Black Friday relates to the black ink bookkeepers use when a company is turning a profit, that is, they are no longer "in the red.