Regardless of how good the leaked version is or isn't, regardless of where it was stored to make it convenient for press to get access to it, regardless of whether or not this illegitimate copy of the game leads to word of mouth sales...the bottom line is someone stole credentials, downloaded a piece of software they didn't have any right to download and then, redistributed it over the internet. All before the game has been released.
That's just flat out illegal. I've never heard of a more black and white case of copyright infringement outside of some kind of Mission Impossible plot where they physically break into the developer's offices using elaborate disguises and make off with a hard drive.
Not every asshat behavior needs to be rationalized away as serving the greater good. Some douchebags are actually criminals and deserve to have the fucking book thrown at them.