Ok, so let's go over what he did.
He used his power on everything other than himself, right?
He never once actually used his own body for anything other than somatic gestures. He punched using things he lifted, he pushed David down. When you're in a fight like that do you really stop to think: "oh, look at these waves on my body, I bet I can push myself around." Or better yet, would you ever think of this: "Hey, I need to dodge really really fast, so I'm going to smash this rock into me so I move."
Can you dance? Sure you can move your feet, but the complicated movements elude you. This is the same thing. He is using brute force in the most basic idea of it. AKA:
That guy over there is going to hurt me and is an asshole, I want him to hurt and me not to. He is thinking about punching, about blocking. These ideas are simple. Stop this, hit this.
Think about moving without actually moving. Does that make any sense? Does it seem more natural than running away?