It's just kind of stupid honestly. This benefits no one, it's this shitty behavior that has existed for years in the gaming community. Hackers target devs and ruin entire projects for what? Some pre release content. Some test videos of early builds? The shit is stupid.
I know they do it to extort the devs, to prove they can, and because it's this insular group of people focused on shit like this that have made this their purpose.
But it's honestly. Just stupid. They're all losers. Sometimes you lose the forest for the trees and can't see just how pathetic you've become. That's all these guys. Complete losers.
If it's the full, genuine GTA5 source code, the community could benefit from it. Tremendously. It means bugfixes where none happened, extensions where none happened, modifications where none happened, and support when none is provided anymore (sure, R* has a pretty good track record in that regard, but still).
It's not legal, but pretending no one will benefit from it or that R* is now leaking billions (because that's what ruining projects is about here) on a decade-old game is disingenuous.