I think that it is perfectly legitimate to view a direct insult to one's skills as a request for a demonstration, and I think that has been the case for pretty much the entire history of the martial arts, both East and West.
Beyond that, I wasn't there. Neither were you. And the nidan in question hasn't shared his side of the story.
I have, however, been thrown around like a rag doll on more than one occasion. My partners had good control; I was never in any danger of injury. It was a good learning experience.
Soi if you were outside in a bar or somewhere else other than a dojo and somebody implied you were useless at Aikido would you see this criticism as a direct insult?Would you then go outside, put your dukes up and teach this upstart a sharp lesson?I have been thrown around by many a shihan in my day , but Ii have never been thrown around by any guy who tried to prove he/she was a big man.As I stated clearly its not the fact that the Nidan got tossed around.I am being critical and condemning the seniors behaviour and his motives for doing what he did.
So if you think someone treating you badly trying to prove his point is possibly ' good' learning experience what would you consider to be a bad learning experience?