Idk, I always interpreted it as a conversation, where you the reader are saying "I know javascript" and Kyle Simpson says that you don't, which is how the book is intended.
I've taken a few of his online courses and he does an excellent job telling someone they don't know js, without coming off arrogant. I think it's mostly because he can explain most issues in depth but as a previous comment pointed out, it isn't really a beginner series. Although, I am not sure "[learning] javascript" necessarily means that the learner is completely inexperienced.