The general idea of this passage is that even students who follow Mr. Wang Yangming often understand only a small part of the knowledge and miss most of it when listening to Mr. Wang's teachings. It's like when we identify a maxima, we only see its male and female black and yellow, and ignore other characteristics of maxima.
For example, children listen carefully in class, but they are at a loss when facing exercises after class. This is because they have only learned superficial knowledge, but have not mastered the essence of knowledge, so they can never use it.
For another example, we want to read more books, learn more knowledge and improve our self-ability after work. But even though we have read a lot of "secrets of success" such as "so-and-so's saying" and "so-and-so's teaching you to learn", why is it that when it comes to concrete implementation, the effect is always poor and can't be achieved?
In fact, this is what Xu Ai said, that is, "seeing its demon and abandoning its so-called thousands of miles."
Zhu Mu Huang Zhu is an allusion in Liezi Fu Shuo, which tells a short story between Qin Mugong and Bole.