There is no danger of it being forgotten. And this is why we have museums and why history is supposed to be taught in our schools, anyway. Those statues were not erected to remind us of an evil, their purpose (as many appeared during the Civil Rights movement) was by segregationists attempting the reassertion of white supremacy---the same reason the marchers and alt-right groups are fighting to keep them up today.
The "white-washing" as you call it, is pretending that these were heroes who deserve statues and memorials, rather than traitors who didn't want to be a part of the U.S. if slavery was going to be abolished. Or, in the case of Columbus, someone who opened the door to genocide of an entire group of people.
Hitler is a part of history. But Germany at least has the decency not to still celebrate him.
