You're right--it IS as though the "official histories" taught in schools represent an alternate history. The "memory hole" Orwell wrote of in 1948 was active at that time in the US: the conversion of the Soviet Union from "our valiant ally against the Nazis" to "our enemy." To do that, history had to be rewritten as you indicate to show instead that "We have always been at war with the Soviet Union" and too many of those who were trying to save European Jewry were--like the ones you list--also "Communists or fellow-travelers." The Fireside Book of Folksongs, found in every school and camp, looked very different in the 1944 edition (which I have) than it did in later ones. In 1944, songs of the International Brigade in the Spanish Civil War can be found alongside translations of war songs of the heroic Russians.