Ukemi teaches us one half of Aikido, I know it's a cliche', but it is so for a reason.
Did Ueshiba Morihei ever teach ukemi? If "I" (as the generic student) have to "figure it out yourself" then how can my teacher take credit for my efforts?
I don't recall Masatoshi Morita or Shibata Ichiro ever teaching ukemi explicitly. Could be I was not paying close enough attention. Other instructors have explicitly taught ukemi but probably 1 part ukemi to 99 parts not ukemi ... guess I picked instructors that missed 50% of the art ... or at least deem me unworthy of such instruction.
I don't mean to poke Mr. Hein as a great number of folks hold this line of reasoning to be true as well - I'm perplexed by the logic. Although, I do like being perplexed as it makes me think.