I'm sure it is. No one has ever gotten away with Bitcoin thefts by arguing 'all I did was input some numbers as allowed to the server and sent some bitcoins to another address'. Is it a good of real world value which you obtained control over without the original owner's consent? Then it was theft and a judge will see it as theft.
It does happen, and I would think (not a lawyer) that in most jurisdictions that it would not be illegal. That case where the guy found a pattern in a video slot machine comes to mind. You are legally entitled to play the game in an authorized manner. Penetrating the server and giving yourself the money wouldn't be the same as playing the game and earning it.
Also in Eve, the money doesn't correspond to money, it's time. You can buy time playing the game with the money. Maybe there are places to exchange one for another, but that's not really the point and would be out of scope for the developers, imo.
If Eve's in-game money doesn't correspond to real money, how is it possible to say "$45,000 worth of in-game cash looted" with any accuracy?
[1]: https://eve-central.com/home/quicklook.html?typeid=29668