The importance of punctuation.

We all know I'm not a history person, so I have no idea what the context of this quote is, but maybe it's just punctuated incorrectly, xkcd. Ever think of that? Change that dash (which shouldn't even be a dash in this argument, really, but rather a colon (I know you can use em- and en-dashes like a colon, but I think a colon says "PRESENTING THE FOLLOWING:" better than a dash does. See? I can't even make the point without using a colon!)) to a comma, and you've got a completely different, if slightly redundant, but more correct statement.