Former Cuban leader Fidel Castro called U.S. President Barack Obama \"stupid\" for saying Cuba needs to make changes to improve relations with the United States. Castro, in an essay published Thursday by Cuban state media, said Obama\'s \"generosity has failed to let him understand that after 50 years of blockade and crimes against our country they haven\'t been able to bow our people,\" CNN reported. On Wednesday, Obama told Hispanic journalists he would be willing to alter the United States\' tough stance on Cuba \"when we start seeing a serious intention on the part of the Cuban government to provide liberty for its people.\" Castro said changes in Cuba would occur \"despite\" the United States. \"Otherwise, the empire would cease to be the empire and Obama would cease to be stupid,\" he said.