According to Chapter 17, why do some people choose the path of Preya even when the path of Shreya is available, and what analogy is used to describe the wise choice?

Chapter 17 clarifies that even when both Shreya (the Good) and Preya (the Pleasant) are within a person's reach, making the right choice is difficult. A dull-witted person, lacking discrimination and detachment, is easily conquered by Preya and embraces it. They become caught in the cycle of maintaining their body, cattle, children, and wealth, thus pursuing only what is immediately pleasant. To illustrate the wise choice, the chapter uses the analogy of a swan (Maral) that drinks only the pure milk when it is mixed with water. Similarly, courageous and wise individuals are said to cling only to Shreya, which is the true purpose of human life.