Other mistake: When Dark Hulk lifts up the middle army tank, he rotates the tank towards the two tanks on either side of it and fires the tank gun at both of them. Since he's holding the tank from the bottom, he has no way of controlling the tank gun, and there's no reason the tank's gunner would fire on his own men.
Other mistake: Throughout the episode, you can see that the animators drew Doctor Strange's fingernails, even though he is wearing gloves.
Answer: The Hulk is a giant brute who smashes everything in his path when he is angry. In Ang Lee's "Hulk," General Ross, played by Sam Elliot, explains it to his daughter.