Well if it was copyrighted then maybe. But this has no copyrights attached...
This part of your statement may not be as true as you think...
The game's archive contains images & videos in it and it is highly likely that at least some of them were created in legal regions that have copyright related laws, which means that someone(s) likely owns the rights to that media. If this is true then there may be implied copyrights attached to the game's media content.
It is highly likely that the game's developer sourced at least some (if not all) of the images & videos from the intertubes, and it is also likely that the game's developer isn't the copyright owner of said sourced media. If this is true then the game's developer is illegally using said media, and it also means that they can't licence the usage rights to said material to any player of the game that resides in a legal region with copyright related laws, thus said player could also be illegally using said media.
If both of the above are true then it is possible that anyone (who resides in a relevant legal region) distributing the achieve could also be seen as as a third-party that is circumventing the rights of the copyright holder(s). Thus I can understand someone being hesitant to upload such a file.