It adds the executable permission (without which, things can’t be executed) to all the files in the game’s directory. You only need to be able to execute a few of those files, and there’s a dedicated permission to control what can and can’t be executed for a reason. Windows doesn’t have a direct equivalent, so setting it for everything gives the impression that they’re trying to make it behave like Windows rather than working with the OS.
It doesn’t have to have been effective. They might just have overestimated how many people would think killing health insurance CEOs was unacceptable.