Well one of the authors (Jeremy Howard) strongly advocates for learning by writing. I think it's a good mission: there is always value in finding better ways to convey information. If you already know this material then it's easily ignored. Other people may be excited about something you already know, and that's fine. Unfortunately that makes it pop up in your news feed and sorry I have no solution for that =).

Edit: Just noticed the other author is the creator of ANTLR, which I recall using in school to write our own languages. Cool!