Picking up a few dropped stitches from this fast-moving thread...
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.
This whole thing so reminds me of the first and second century of Christian formation. The original followers of "The Way" did not have a creed of belief at first. A rich variety of theological views thrived (Gospel of Thomas, Epistle of Barnabas). Once a big geographical expansion occurs (After Pentechost) and the original apostles begin dying out, apostolic succession becomes very important (1st Clement; The Gospel of Mary Magdelene) and then those who take charge create creeds, not so much to proscribe outsiders, rather, to fence out fellow Christians who's views were different (Tertullian, Nicea, Chalcedon)
These last few years of watching the debates has been an amazing one.