The people destroying those statues of Lenin were not seeing them on Youtube; they had to live in their shadow every day. Preserving statues, buildings, really any kind of object is always a balancing act between the needs and desires of the present versus the historical value of what's being preserved. For reasons already outlined, these kinds of Confederate sympathizing statues are a hilarious extreme on that balancing act, being totally hateful to the values of contemporary society and having almost zero significance as cultural artifacts.
It only takes a small bit of imagining of modern Iraqis continuing to live underneath a 40-foot Saddam Hussein, or of modern Germans living in a forest of Swastikas and Nazi eagles, to come to the obvious conclusion: tear them the fuck down.