A personal account -- however valuable -- is not that kind of investigative journalism; at most, it might feed into someone else's investigative work, where they go in and get access to documents, get other sources (including people) to corroborate the information, etc. That kind of thing is what the Pulitzer organization is trying to recognize.
To adapt your analogy:
>Counter point: If an indie game dev makes a non-aaa game that enthralls people, would that not be a contender for a game-of-the-whatever award?
If the award were for groundbreaking new games, then no, they shouldn't discriminate against someone merely for being a low budget indie. But if it were merely a mod to some existing game that keeps the core functionality, then the award would be inappropriate. Another category could still be merited, though.
Counter point: If an indie game dev makes a non-aaa game that enthralls people, would that not be a contender for a game-of-the-whatever award?