My point is that he advises to "step in (and cut)" even without an opening. Not only is that not martially sound, but isn't that the very scenario we train for? Don't we hope our opponent "steps in " without an opening? Imo, that's bad advice and a point of evolution.
Sure if you are taking it literally and without high degree of understanding. He is talking in poetic form. And with any poetic form there are levels of understand written it. I first thought like you, but after years of study in Aikido and other knowledge I came to realize the emphasis isn't on the literal. He is talking about right action. But that isn't all, also it is about strategy on many levels. Going beyond the impossible, or doing the impossible, it is determination to succeed where it doesn't seem you can. I hate to quote O'Sensei, but I think he said he learned Budo from his teacher who fought in many life and death situations, and was a fighter-violent, killing enemies. There then must be some credibility to what he is saying.
Really, we are way past the usefulness of this discussion.