I don't like categorical dismissal of the idea of 6DIF. I do not think that there are topics games should shy away from like this just because they're games. I think that there's absolutely room for using immersive experiences of playing an FPS to imagine and express experiences of characters in the space have to deal with. Simply put, there is no artistic space I think that games as a media form can be told 'you can't go here.'
However
the Games Industry that exists and gets to make games with licensed guns in them and military support and the media access that 6DIF has, cannot handle it because it is a system of entirely crass commercialisation compliant with a dominant media structure that wants to use Fallujah and the US invasion of it as a sort of 'seriousness' it can use to cloak its procedural Iraqi Terrifier Sim game