Why a topic is important, and arguments about that, are relevant. While some comparisons and alternatives can be discussed as part of that, addressing whether specific other things are important (e.g. knitting or football) is broadly unnecessary.
A difficulty with learning opposing arguments well is the lack of debate or of people willing to answer questions and talk about those arguments. If you read a book and think the arguments are bad, how are you supposed to check if you understood it well unless people who think the book is good will give feedback or debate or something?