Why? I think you watched this before you had your morning meditation and coffee Seriously.
Compare and contrast (Not for skill level, but just in how the body is being held) the original posted video with the two below.
Note how both Shioda and Tohei hold their body forward. By that, I mean that they don't open either hip out to the side, no matter where uke touches them. Head centered on the body, whole body pointing forward. Matsuoka opens his hips outward quite often.
I think Shioda is the easiest to see how all the greats held themselves. Relook at the videos. They all held their bodies in a similar fashion. Almost as if they were always pointed straight ahead, no matter where uke touched them. And when they moved, they still seemed to be looking straight ahead. Look at Shioda's ken clip, his hips always remain straight forward. They never open out to the side like Matsuoka does.
Just one noted difference.