Rated M?!

Why on earth is this game rated M? It says for "Blood and mild violence" but I've seen worse T rated games. Games like the Tony Hawk series, Whacked and Destroy All Humans have tons of objectional material and are rated T. So why did this game have less than all of that and still get rated M? I just got done playing the demo and it's not that bad. In fact, in the first case there's barely any blood at all! It looked like there was hardly anything that parents would find objectional to have their kids under age 17 see. The only part that maybe parents might not like is the images of the bodies. But there's not anything on it that most M-rated games are rated for. There's no sexual innuendo, no nudity, no language, no drugs or alcohol or any of that other stuff that most parents find objectional. So why'd it get rated M?