The shoulder pads you see are a 6 ×3 foot . Essentially they are the arm span of a real life palyer . So anything that happens in that range is up to interpretation .
One could say the defender grabbed on to the qbs waist and his right arm was free to make the throw away .
Remember, this is not a video game. What you see is only a 2D representation of a text result. JDB is a one-man operation and he is busy enough without trying to become the next Madden programmer.