It was just not explicit that it should be OFF by default. Reviewers fault. Microsoft, made a Marketing stunt of enabling it by default 2 years ago, in practice killing the point of DNT and setting back the industry several years.
With a default option DNT would have no reason to be honored by any site owner. We could be enjoying native DNT tracking right now if Microsoft hadn't done that stupid dick move 2 years ago.
How many years we'll need before the number of users that already have DNT set to ON by default are negligent is hard to measure.
This should be a post apologizing for the trouble they caused and for destroyed the point of a W3C proposal that set back the industry for several years. Instead it looks like another Marketing stunt.