I have seen this phenomenon so often in explanations/tutorials of different things. People seem to not have a concrete target audience in mind. They simply write of cuff.
[1] http://matt.might.net/articles/programming-with-continuation...
[2] https://pages.lip6.fr/Christian.Queinnec/WWW/LiSP.html
[3] https://www.cambridge.org/core/books/compiling-with-continua...
Nearly every 'beginner' lesson or tutorial or book on programming that I have seen state in the beginning that 'some programming experience recommended.'