Erm, What? Arendt was an amazing philosopher and yes she wasn't perfect. And yes, the first part reads as a press release for her, which is just bad writing.
But that book you bring up is just odd. I don't like just pointing fallacies and calling it off, but that seems both yellow and ad hominem to the worst degree. Do we really need our cultural critics to be perfect? It is widely known that Rousseau was a terrible person. That doesn't require research that requires reading his autobiography. He admits that. So the social contract movement is now void? That seems odd.
Also, if we are going to talk about important philosophers that are less than perfect there is a shining lack of Heidegger. Still widely taught, cited and talked about. One of the most important philosophers of the 20th century and a tad more questionable past than Hemingway.