I think that multiplayer maps etc are just as much art as any other piece of art. I think the difficulty comes in that alot of people can make good maps and nowadays alot of people can paint well, so that being an artist is not such an exclusive club. Its not like the Renaissance anymore where there are only 20 famous artists around, there are artists all over the place!
I think that leads alot of people to think that only completely wierd shit has artistic merit which couldn't be farther from the truth