It's because the big studios are the ones buying all the advertising which is where the magazines and sites make all their money. As a result game magazines are very hesitant to publish an overly critical review of their flagship games (particularly the ones with big advertising budgets) for fear of the ads being pulled and losing all that revenue. Stardock, on the other hand, is an indie studio with a small advertising budget, so consequently they are less reluctant to be critical.
Edit: this comment was made in the context of the discussion about there being a double standard, which certainly there is and is easy enough to understand if you follow the money.
People only see isolated gaming studios, in reality most of those gaming studios are owned by very few key players/investors.
Game review sites, sell customer influence to them, and through them they try to make the gaming industry an oligarchy.
You can't even begin to imagine how much it pisses those people, the fact that Brad is the owner, the CEO, the Game designer, and a success story.
He has also stated that he isn't doing this for the money, he has enough. He's doing it cause he likes what he does. And for that he has my utmost respect.
He speaks openly to the press, because he has no fear, no one will fire him cut his shares or demote him. If he becomes annoyed he shows it, he won't let anyone look down on him and he sets the record straight because he can afford to do it. Hence the slanderous approach from the news and the double standards.
As many people have said in these forums, although it is evident to me. The world isn't a place filled with roses. I stopped reading reviews ages ago, right after a friend of mine working for a gaming magazine explained to me how magazines and reviews sites really "worked".