"the racist Civil War general Robert E. Lee" is a historically inaccurate portrayal.  Robert E. Lee was actually from the south but not for slavery but believed in the rights of States. He was widely respected by both sides for his treatment of prisoners and African Americans. 
  
If you look back and judge people by today's standards then even Abraham Lincoln who wrote before he won the Presidency that African Americans were inferior would be considered racists.  

No doubt a tough issue. Racism is a curse.  But how we treat and judge historical figures has to be tempered with and placed in context within the values of the day and whether they help progress the world to the values we agree on in today's world.