[vortec94]

They shoot that way because that’s the way they come in the box. Hat backwards? Demonstrating that they don’t know how to operate a hat. Probably why the switch to hoodies.

[Falcon4.0]

Seriously. They shoot that way because of the natural tendency to pull the gun to the side with the trigger pull.
A person is taller than they are wide, so pulling the gun up a little gives the perp a better chance of hitting his intended victim, verses pulling the shot off to one side.