He's probably going to have to change his gearbox now. Does that make you all any happier?
Hamilton's penalty was McLaren's penalty. You break the technical regulations and you can be disqualified (think Button and BAR). It doesn't go to the stewards to decide the penalty because it's a straight forward infringement of the technical regulations.
Maldonado, on the other hand, wasn't breaking any technical regulations - just his own car along with other drivers cars.