Nothing was "stolen", the state of the blockchain was altered in a way you did not want to occur. Now everyone using bitcoin agrees that any transactions you issue are invalid because you don't have any funds on the address you'd like to pay from.
Convincing a judge there was an actual theft is going to be your first challenge; unless laws are updated the theft of bitcoins doesn't obviously fit into existing rules that were designed around physical goods or fiat currency.
Yes, but looting the corpse of a fallen enemy on an MMO could be described the same way, as well. Should that now be considered a crime?
The line gets very blurry especially when you start accounting for MMOs with official real-world economic links like EVE.
I'm not saying I think theft of bitcoins shouldn't be illegal, just that the situation is a lot blurrier than some people seem to think, and until someone is convicted for (or at the very least charged with) stealing bitcoins there's really no point in debating the matter.
There are laws specific to electronically stored fiat currency. They don't automatically apply to World of Warcraft gold, spaceships in Eve Online or Bitcoins.
Convincing a judge there was an actual theft is going to be your first challenge; unless laws are updated the theft of bitcoins doesn't obviously fit into existing rules that were designed around physical goods or fiat currency.