In order to sell books, the story and narrative has to be compelling. Is the story of a Canadian guy making millions of dollars at his trading desk quitting his job and starting a company (we love startups!) that may undermine a controversial trading tactic a compelling story? Absolutely. Is the story of Einhorn or Cohen or Icahn doing things like insider trading or activist investing equally compelling? Probably not, since it's on the cover of the WSJ or on CNBC every week.
Michael Lewis does not have a responsibility to educate main street about the nuances of HFT, although as a secondary benefit of his noble pursuit to sell more books, he does shine a light on the topic. In this regard, Lewis is exceptionally successful. He's sparked a debate, he's created controversy, he's made smart people discuss a topic they had previously less interest in.
Think about what Moneyball did for professional sports? Lewis was hardly the first (e.g, Bill James) but he popularized it so we, the general population, could discuss the topic with some conviction and knowledge. If he can do the same for HFT and trading in general, then good job. And he sells more books.