Certainly it is a disgrace for an American to bow to a foreign monarch as if to a superior. That is very clear.
But I suspect you are right. The Japanese have always been extremely insular. If you are not Japanese, there is no way that you can become Japanese.
At best, I suspect that the Emperor and Empress regarded Obama as something like a puppy trying to shake hands. Cute, but rather funny.
He’d might as well have given them a Samurai DVD pack.
Hey that would be way cool (Poorly dubbed Jap TV turned Australian school playgrounds into Death Grounds back in the 60s)