They were all unwitting victims of an Italian journalist who fabricated interviews, according to this Talk of the Town piece from The New Yorker:

The real scandal revealed by the interview, however, came at the end, when Zanuttini asked Roth why he was so “disappointed” with Barack Obama. She translated, aloud, remarks attributed to him in an article by a freelance journalist, Tommaso Debenedetti, that was published last November in Libero, a tabloid notably sympathetic to Silvio Berlusconi, the Prime Minister of Italy (who is embroiled in his own sex scandals with much younger women). “It appears that you find him nasty, vacillating, and mired in the mechanics of power,” Zanuttini said. “But I have never said anything of the kind!” Roth objected. “It is completely contrary to what I think. Obama, in my opinion, is fantastic.” He had never heard of Debenedetti, or of Libero. The interview, with its bitter judgment of Obama’s banality, failure, and empty rhetoric about hope and change, was a complete fabrication.

The journalist attributed negative statements about Obama to Grisham and Roth in fictional interviews. Grisham, it turns out, is suing. Roth can't be bothered.