This book seems to promote blind devotion by telling people to avoid argumentation and just have faith. Isn't this just a technique to shut down critical thinking and questioning?

The text does indeed advocate for faith over logical debate. Chapter 2 explicitly states that where there is a mind for argumentation, there is an abundance of ignorance and Maya, leading only to unhappiness. Readers are advised, "Do not establish your own side, do not refute the other side, Do not engage in dualistic explanations." The stated purpose is to foster devotion, which is said to destroy ignorance. According to the source, for those who listen with true feeling, faith will arise, leading to self-experience, self-bliss, and knowledge of one's true form. From the perspective of the text, this is not about shutting down critical thought but about transcending what it calls "false logic" to achieve a deeper spiritual realization.