What is insulting is to say that all the direct students of O Sensei had no idea what he was doing and therefore made stuff up. What is insulting is to state or imply that these direct students must be mistaken or dishonest when they recount stories of being taught directly by O Sensei. What is insulting is to state that the direct students of O Sensei had very little experience with him, that Doshu watered down the art intentionally, and all the other things that are frequently repeated.
I don't think that O-Sensei was directly teaching anyone exactly how to do anything. They had to take what the could get and put their own spin on it. Here's a quote from Henry Kono, a guy who studied at Hombu daily for 4 years.
How often did you see O-Sensei?
If he was in the back of the dojo he might come out every day. If he was away, you might not see him for three weeks. If he was there, he might come out for five or ten minutes then go back in. I saw him about 300 times in four years. He never explained what he did, he just did it! This is what I mean by magician. He did it and if you couldn't discern what he did, there was no way to figure it out. He never explained anything but he left hints which were very difficult to discern because of the way he stated his ideas in very short phrases that no one could understand.
I saw a tape of Shioda Sensei being interviewed in England. He was with O-Sensei for ten years from about 1930-40, he said O-Sensei never explained once in that 10 years as to what he was doing!
He wasn't a teacher in the sense that he was teaching. The Japanese may look at that as teaching, but in the western sense it isn't. You had to intuit what he was doing and saying, read between the lines, so to speak.