Making an inflamatory statement like that, even if it's a "mistake, even if it's immediately retracted, still plants a seed in the minds of those who would be inclined to believe it. Look at how many people in the US still believe that Saddam had WMDs and a direct connection with Bin Laden. Nevermind that both contentions have been proven false and that the government has admitted as much. When people want to believe what someone says, they'll believe it despite retractions, corrections, and apologies.