...This guy passed the point and kept on running.
Hard to say based on 70". Maybe he did, or maybe not. It also depends on the horse. Cowboy, like a lot of lesson horses, is pretty hard-mouthed. With time, he is softening, but that is in a normal situation. If he decides to be a pain, then he is very hard mouthed.
With my other two horses, pinkie pressure is about all it takes on the reins. Even when they get excited, a pinkie of pressure as each shoulder goes forward, and in a few strides they will respond. But when Cowboy gets excited, he switches from wrist pressure to full arm pressure.
There are a lot of things we don't know from the video, including the horse's personality and background.
Like most on the thread, I'm not saying I admire the way the guy is handling things. I ride with a snaffle or rope halter, and my goal for all of my horses is to get to where reins are rarely used. For me, normal riding includes slack in the reins, unlike the English approach of contact.
However, I'm not willing to jump in the guy's chili without knowing a lot more. Nor am I willing to condemn a sport (reining) based on a short video.