Stating that pros generally have slower backswings compared to the average amateur player is one thing, but I'm not sure where Mark got that the average pro is between 1.2 to 1.8 seconds.
I just looked at random youtube videos of Alex, Little Ko, Dennis O, Efren, SVB, and Kaci, and they all had backswings 1.0s and below, averaging around 0.7-0.8s.
I think the main takeaway is that pros don't "fight" their backswing by thrusting forward until the backswing has stopped. I doubt he actually timed a bunch of pros and averaged it out