I really liked his message of listening to your horse and your gut over listening to people yelling at you that you MUST punish the horse. I've run into people like that with my horses, and I've run into people like that when I ride their horses.
Horses are trained though action (of handler) and reaction (of horse). The entire thing of punishment means the handler/rider is not paying attention to the behaviors of the horse and guiding them into what they want to engender, but rather waiting for the horse to make mistakes and then trying to surpress unwanted behaviors....doesnt work to easily advance horses.