“Those who are so upset about this just happen to reside on the LEFT of the political spectrum.”
“Wonder why?”
Because the Democrat/Progressive left are in full cover-up mode over their slavery advocating. insurrectionist, rebellious Confederate past. They are in full cover up mode about their history, and they do not wish to have tangible reminders of that reality.
Whoa! Hold back on that high horse.
Remember, twice as president Lincoln took an oath to defend and preserve the pro-slavery United States Constitution.
If you want to you can argue Lincoln wasn't serious about upholding the pro-slavery United States Constitution and that, if fact, he did everything he could to destroy the Constitution. There is much evidence to support that argument.