It's not about swordsmanship, it's about failure to be able to make your body do a simple task the way one wants it done.
He used word 'sword' - not for example fork, baseball bat or any other object. So we are talking here about swordsmanship. Cutting with a sword is not a simple task at all
It also means to me, he mistakenly thinks that bokken practice and sword practice is the same.There some quite strict rules how to use correctly a sword to cut.
I think you are reading too much from his post.