There was an uproar from critics who argued that the gesture was clumsy and opportunistic, if not cynical, as Mr. Koons didn’t have a direct connection to the terrorist attacks. “The general outcry was in part caused by a form of outdated anti-Americanism, but it was also a sincere, offended one,” said Guillaume Piens, the director of the Art Paris Art Fair. “Whenever artists touch on memory and victims, it’s hard to see an uninterested, mere artistic act only.”