Serious case of cutting off the nose to spite the face here. Sure, people are making content (and a bit of money on the side) from using Nintendo's content. However, it is the cheapest form of advertising yet some of the most effective! And they don't even need to contract companies to do it! Usually when I am considering purchasing a game, the very first thing I look for is in game footage on YouTube. Yogscast (as annoying as they are - grown men acting like teenagers, psssh) was one of the reasons I bought GW2.
Sure, I can understand, you wouldn't want people making money off of your product. But to piss off the people promoting your game? Not smart at all!