Sorry but you cant call our country the 'most enlightened' if we hide historical truths, making many people totally ignorant about one of our most famous Presidents who many even view as their savior.
Also you cant say we "eventually stand up and right her wrongs" if in fact we still allow history to teach that a President trashed the US Constitution that he swore to uphold and defend.
But of course we cant say the truth that Lincoln committed treason and deserved to be hanged.
Millions of American kids and ignorant adults, who still believe Lincoln was the greatest President ever, would suffer from even worse self esteem problems than they do now.
And we cant tear down a memorial to this criminal President because school field trips still go there and pretend that this criminal was the greatest President ever.