It's like making an exhibition called "The Art of Cinema" and having Star Wars, Die Hard and Grease but nothing by Godard, Bergman or Pasolini. Very liberal, indeed.
And this is why you don't let the Internet vote forth the most artistic anything (especially not the gamer community). It tends to confuse good entertainment with good art. Sure, Super Mario may be great for what it is, but what it is isn't art.