Exactly Dan.. that is within the whole 'attack within your defense' and my opposition to the statement Michael made that 'you can do it offensively OR defensively'
As you point out, the offense is within the defense. As you neutralize the push by turning, and stepping rearward, you are also expanding forward toward your opponent, leveraging the turning/torque to generate forward power. where there is a backward movement there is a forward... where there is an up, there is a down... where there is defense there is offense.
back to that yin/yang thing again.
Also notice, the defense weakens your opponent so you can (at the same time) use your strength against his weakness. in Snapping Twig, neutralizing the push weakens your opponents left side by moving it off center (like the effect of walking down stairs thinking there are 11 steps but there are really 10)... while experiencing that phenomena, you use your strong right side to attack his weakened left... while creating an angle that eliminates his right side (canceling depth)