The author wants the reader to understand that, bullying isn’t okay and I don’t know what book you have read but i’m assuming the popular people are bullying people who are assumed as not “cool” so i’d say it’s not okay and that no one deserves to get treated that way
This paragraph lacks sentence variety because the writer, started sentence after sentence the <em>same way</em>. didn't include structure with proper legth or that provides emphasis. <em>Prepositional phrase, adverbial clause, adverbs</em> (absolutely; naturally) or some<em> connective</em> (therefore; and; besides etc) are great help to <em>avoid monotony.</em>