Firstly, no demand sits on the weakness side, and as an absorption bar we are suggesting it as a potential sign of strength.
and Secondly, the text book perfect no demand bar is described as "a narrow spread up bar, on low volume, closing mid to low", and is seen as a confirmation bar of previously seen weakness.
This type of bar just doesn't fit in with conventional or traditional VSA or Wyckoff analysis, so I wonder if it is a more modern interpretation, perhaps created because of online and automated trading, both of which were not really present when Wyckoff was reading the ticker tape, or when Tom was computerising his interpretation of Wyckoff's work which eventually became VSA.