I've never seen it working almost exclusively for defense contractors, but government contractors have very stringent anti-discrimination laws and federal labor laws they must be compliant with if they want to keep those government contracts. I see a lot less casual racism working in military offices, too--that shit isn't tolerated. Also, we don't post about the latest developments at work in public forums, and if we did, the only people who would be interested are our professional and/or national rivals.
I get the impression that game companies tend to attract young, very competitive developers who think they are the hottest thing since sliced bread, and haven't had the life-lessons imparted by experience to convince them they aren't all that yet. And then, there's your gamer customers... if I want to experience the bottom half of the bell curve, I either go to general news sites comment threads, or gamer forums.