There's a rather pronounced difference between "erasing" history and addressing the presence of statues which were erected to celebrate Jim Crow Era institutional racism and white supremacy.  

Indeed, slavery is one of the blots on our history.  No one, to my knowledge, is suggesting that we should "erase" that history.  On the contrary we need to remember it.  We need to understand it. We need to erase not the history of racism, but the racism which still exists today.  Removing the monuments which were erected to celebrate that racism is a step toward doing so.  It's time black Americans should be able walk the streets of American cities without walking past monuments celebrating the Era of Jim Crow which defined them as second class citizens.. monuments erected to remind them  of who's "boss" and who's "boy."  As a matter of fact, removing those monuments which honor that racism is, to use your phrase, "changing something that might improve people's lives today."  Gary Crum