Anybody believes that O sensei could do the techniques only with particular behavior of uke?
Sorry but this shows that you don't understand the method of transmission in Japanese aikido. It is very clear (in Japan, at least) that during a class there are two lessons being taught. One is for all those watching, this is how we move our hands and feet, etc. The other is for the person taking ukemi, this is how it FEELS.
Prof. Goldsbury can certainly explain what he meant if he wishes, but I wonder if it might not fall on deaf ears if you don't understand the distinction in the first place. The idea is that O'Sensei expected correct ukemi because he was transmitting something directly to that person, not because he was interested in showing whether he could do a technique or not to the peanut gallery.