Rhetorical questions are asked in order to persuade the audience and prove them the statement rather than providing information. Mack utilizes the rhetorical questions to make his audience think about the topics asked as questions. The thoughts of different types of people are analysed.
By making the audience to think about the topics Mack keeps the audience engaged. The audience also find it interactive and communicate their thoughts on the topic effectively. Hence these questions set stage for Mack's argument and engage his audience.