As far as I am aware, this duel didn't happen in Funakoshi's dojo, while a class was in session.
Also, we both posted on the red light district training at the same time, and yes, this had a big impact on Motobu as both a teacher (different understanding because of practical application learned in the "doing" vs theory driven education) and as a fighter.
I doubt he would have stepped into a fighting ring with a Russian boxer if he hasn't done his red light training.
I would hesitate to call picking fights training.
It was Motobu himself who in an interview said he barged in on a class. He didn't mention menacing GF with his fist though.
I disagree with Mr Noble. From reading his work I think GF was fine with kumite, but that he didn't feel most of his students were ready. I think GF was against turning karate into a sport.
And again, all this leads to a big "So what?!"
Because Motobu was a better fighter it doesn't make the same true for his students. The art was passed down via kata so the proficiency of any one teacher is meaningless unless you are talking about their teaching skills.