While I do not agree with the first sentence in your post (comparing ANY human to ANY animal leads to a very slippery slope down to genocide), I see a certain point that those black anti-Confederate protesters should have a better grasp of their own history.
http://www.paulcraigroberts.org/2015/04/13/power-lies/The Lincoln Memorial was built not because Lincoln “freed the slaves,” but because Lincoln saved the empire. As the Savior of the Empire, had Lincoln not been assassinated, he could have become emperor for life.
As Professor Thomas DiLorenzo writes: “Lincoln spent his entire political career attempting to use the powers of the state for the benefit of the moneyed corporate elite (the ‘one-percenters’ of his day), first in Illinois, and then in the North in general, through protectionist tariffs, corporate welfare for road, canal, and railroad corporations, and a national bank controlled by politicians like himself to fund it all.”
Lincoln was a man of empire. As soon as the South was conquered, ravaged, and looted, his collection of war criminal generals, such as Sherman and Sheridan, set about exterminating the Plains Indians in one of the worst acts of genocide in human history. Even today Israeli Zionists point to Washington’s extermination of the Plains Indians as the model for Israel’s theft of Palestine.
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The War of Northern Aggression was about tariffs and northern economic imperialism. The North was protectionist. The South was free trade. The North wanted to finance its economic development by forcing the South to pay higher prices for manufactured goods. The North passed the Morrill Tariff which more than doubled the tariff rate to 32.6% and provided for a further hike to 47%. The tariff diverted the South’s profits on its agricultural exports to the coffers of Northern industrialists and manufacturers. The tariff was designed to redirect the South’s expenditures on manufactured goods from England to the higher cost goods produced in the North.
This is why the South left the union, a right of self-determination under the Constitution.
The purpose of Lincoln’s war was to save the empire, not to abolish slavery. In his first inaugural address Lincoln “made an ironclad defense of slavery.”
And that's why all memories of the Confederation and the constitutional right to secession and self-determination are attempted erased now within the USA, just like USA is violating these same rights across the globe.