Wait, the monument thing is all about the conclusion that Lee is "no hero"?
Vandalizing the monument is obviously wrong, on the grounds of defacing public property, etc. As someone in the article said, "If you really want to make a statement someone could have put a status on Facebook saying hey I don't like Robert E Lee."
But I don't see that the statement itself displays historical ignorance. It's an opinion. There's no requirement that everyone consider Robert E. Lee--or Lincoln, or Forrest, or John Brown, or anyone else--a hero, nor any intrinsic level of historical knowledge implied by drawing a personal conclusion about their heroism.
I must be missing something. Is it really a requirement now that everyone must consider certain historical figures heroes, or else they're ignorant of history? Because I don't divide any historical figures into hero-vs.-not-hero, I just take them as they come, but apparently I'm studying history wrong.