When it was written, a beginning C programmer was most likely coming from a background in assembly and accessing the computer as a professional in the workplace or a student with substantial privileges. The intended audience was sitting near the cutting edge and was assumed to be sophisticated. Data validation could be left as an exercise for the reader in good conscience.
This audience is distinctly different from those who learned programming typing code from magazines and Shaw's current audience for whom he is simulating that experience.
Editorially, K&R has chosen to remain a slender tome. It has let others create fat cookbooks and "for idiots". Forty years on, Shaw criticizes the Wright Flyer by the criteria of Second World War aviation.
We don't hold K&R on a pedestal because of its pedagogical methods, but because of the power of the language it describes. The C Programming Language was a byproduct of creating a language.
Kernigan and Ritchie were programming. Their book is properly judged by different standards than Shaw's educational project.
None of which is to suggest that Shaw"s project may not achieve a comparable level of esteem