Picking up a few dropped stitches from this fast-moving thread...
But couldn't the claim be true and also be a big "so what"? People say all kinds of things; not every statement is of deep significance. Unless you're some kind of fanatic, surely you don't think everything O-Sensei ever said was intended as some "here's the eternal truth" statement. And, if you accept that (and I know that many don't), surely the guy was allowed a tossoff remark now and again that just didn't mean that much. Maybe, if we really want to know the truth of history, we need to consider the context of historical figures' statements before assigning importance to them.
But part of the base argument is not just what he said, but where and when he said it. The translations of his only written training manual. Hardly likely to an offhand remark, surely? The doka. Suggest to a poet that any line--or word--in their poem is just tossed off, doesn't mean that much. Then duck. His students come to him and ask, "Why can't we do what we do?" A challenge within the Japanese teacher/student relationship. In that culture, this is the moment when the teacher is challenged to crystallize their teaching. And he says, "You don't understand in-yo ho."
No, these sayings were the moments when O-Sensei was trying to teach. They weren't offhand remarks.