He is a Western Trainer. He does not want a horse that hangs on the bit. He wants 'self carriage'.
What English riders see is a horse that is 'behind the bit'.
What Western riders see is an English horse that 'falls apart' without contact, leans on the bit and cannot carry itself. I have seen many high level Dressage riders with white knuckles.
I have ridden and shown both ways and have had quite a few horses that showed well both ways including a mare that I field hunted and qualified for the AQHA World Show in Reining and Hunter Hack -- all in the same year.
A lot of what the constant flexing accomplishes is that it puts a novice rider that has little skill in a place where they do not get hurt. Clinicians have found that few novice riders stick with any program long enough to become accomplished riders that can ride without a 'crutch' or a means to stay safe on a horse that they could not otherwise handle or ride. Teaching a horse to give instantly to one rein keeps the Dummies from getting killed.
He will come out of this demonstration with a method that Dummies can use to take a TB that would otherwise be WAAAAY over their heads and can stay safe on and may ride well enough to not get killed.
While PP keeps people on the ground for years to keep them safe, CA puts them on a horse they cannot ride and keeps them reasonably safe.
So, take it for what it is. Just like a REAL trainer or an accomplished rider does not need a round pen -- a real trainer and an accomplished rider do not need a One Rein Stop or endless lateral flexing to teach a horse everything it needs to know.
These are crutches that work for Dummies that buy horses that are way over their heads. It beats riding in a 60 foot round pen for a year and coming out of it with a mad horse that they still cannot ride.
I have conducted enough clinics that I know you have to teach the poor riders with spoiled horses that come much differently than you would teach an aspiring rider that wants to become competitive or wants to train professionally some day.
I hope this sheds some light on a subject that many criticize because they do not look at it in the light of a Clinician that is trying to get people on horses and keep them safe -- people that do not have much skill on horses that are not really suitable. Been there -- done that -- have the tee shirt to prove it.