No one alive today in the United States has been a slave or owned a slave, (unless they come from a radical Islamic area or is a victim or perpetrator of the sex slave industry). No one alive today was a participant in either the Wounded Knee or Little Big Horn massacres. No one alive today was a witness or participated in Columbus' discovery of the New World or any of his alleged crimes against the natives. Not a single person breathing now witnessed or engaged in any of the battles of the Civil War or observed the death, ill health and horrendous conditions suffered by the prisoners of that war by both sides.
Atrocities, injustice, torture and man's inhumanity to other human beings has happened throughout the history of the world. These evils are happening today, and unfortunately, will happen in the future. The heinous acts of the past should not be forgotten or swept under the carpet. They are history. Reformation can only occur from a study of past events.
An obsessive focus on sinister historical events is a dangerous occupation and can lead to criminal acts such as tearing down or vandalizing statues of Columbus or the Founding Fathers or Confederate soldiers. Just because the radical leftists who commit these acts feel justified does not make them any less of a crime. These are acts of revenge for real, imagined or alleged wrongs that occurred decades or centuries ago. One can't change the past. The vandals committing these crimes seem to want to erase history. It won't work. They are in a miniscule minority. They don't really articulate their complaints. There are enough citizens who revere history and deplore vandalism, who will demand that law enforcement arrest these criminals.
The study of history, allows us to see the wrongs of the past, but also enables us to see what actions were taken to correct those wrongs. The neurotic obsession with past wrongs causes those centering on those events to minimize any corrective action and justify almost anything they do, however criminal and/or violent. Those Antifa activists don't see anything wrong with destroying property or physically assaulting those who oppose their “enlightened” views. They see nothing wrong with shutting down opposition speech because, in their opinion, anyone who disagrees with them is a Nazi, white supremacist or racist and any words coming from their opponents are “hate speech”. Thus, they think it is not only their right, but their obligation to stop such ideas, “by any means necessary”.
Distortion is the ultimate outcome with an obsession with wrongs of the past. Beside the failure to see the results of restorative actions, this myopia causes a hypersensitivity that manifest itself in the banning of books like Tom Sawyer and To Kill a Mockingbird or forbidding children from wearing certain Halloween costumes. The sufferers of this disease have become so excitable that they react to imaginary slights. They have even invented terms for these phantom insults: microaggressions. If they can't find any direct evidence of an evil, racist or Nazi intent, but feel that the speaker or writer has such an intent, they call it a “dog whistle”.
The best analogy is the driving one: If you only look in the rear view mirror, you may know where you've been, you won't know where you are or where you're going, but you'll be heading for disaster.