also this quote from an actual principled anti-slavery person:
I am quite certain that the crimes of this guilty land will never be purged away but with blood. I had, as I now think vainly, flattered myself that without very much bloodshed it might be done.
- John Brown
This is a guy from the 18th century speaking his thoughts about his time, which was quite violent. There is no reason to believe he was a prophet seeing 250 years into the future of the nation he helped create, or even that he was some kind of ultra-insightful historian who understood all the cycles of the world better than all the historians before or since his time.
He was just a guy in a time. A smart one, but just a guy.
its seems more like he was responding to a nation that was already created and the black panthers would prove that he was right about 100+ years later.