It's not that hard. Moving a few numbers around in a bank's mainframe could be described the same way.
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.